Hi Frank,
It is really good to see a teen ask these sort of question, it would be foolish to believe anything without thinking it through first. That being said, Christianity is a lot more complex and has many level and takes YEARS to fully understand it. I think that many people give up their faith before having the true ability to understand it's significance. I am glad that you came here in your search for answers, I will try to give you my personal reasons for choosing faith, though I cannot speak for the Church. It's a bit long so please bare with me

I too love to learn. I am in my 20s and I thirst for more of this knowledge every day, and for that I am thankful. There is still so much for for me to learn about my faith but God has blessed me with an open mind and a need for Him in my life. My background is such: I grew up Protestant, but with a Catholic father and grandmother (she doesn't live with us though). I went to Public school and besides going to protestant Sunday School and saying grace at meals, we didn't do to much faith formation as a family. I attended and graduated from a Physical Education (Health Sciences) program from one of the top Canadian Universities and I just past my one-year anniversary as a Catholic! In my teens I also started to question my faith while public society put pressure on me to drop religion, but I just couldn't give up Jesus.
JESUS IS REAL. It's not just the Bible where Jesus is documented, but also in Roman Historical documents, the Dead Sea Scrolls(found in this PAST century) and the Muslim Holy book the Koran, and in here his biography compliments the Gospels, including being born of the Virgin Mary and many of his teaching and miracles (they just don't believe in His Divinity, or the Holy Trinity). There is no debating in ANY educated community no matter their Religious beliefs that a man named Jesus lived and was revolutionary. The only debate here, is weather or not Jesus is indeed the Christ. Here is why I BELIEVE JESUS IS THE SON OF GOD:
1) Revolutionary thinking:
So here's the deal...It's 2000 years ago and this guy Jesus comes around saying he's the Son of God. Times were tough those days, as I'm sure you know from watching History television, yet here comes Jesus and he's able to gather quite a following with his teachings and miracles. People would have EXPECTED A GOD or Christ to come full of Glory and power and conceit. Yet Jesus was born of the humble, and remained humble through out his ministries. This would be unheard of for a Royal or ruler to act in humility! Instead, our Jesus came to heal the World and serve the sick and the poor. Not very typical for the elite back then.... And since Jesus obviously wasn't looking out for his own interests and was completely giving, even to the point of death, why would he proclaim to BE the SON OF GOD? This would go COMPLETELY against his personality for him to lie about this! He wasn't looking for that kind of attention!
2) Documented Miracles:
Loaves and Fishes, Water to Wine, Blind seeing, lame walking....Remember that each Gospel is written by a different author. It's like today when something big happens 8 different news agencies will cover it, each writing their own account of what they saw. You can look outside the Bible for external accounts as well in the Koran, dead sea scrolls etc if you're not convinced. These things happened, were witnessed by thousands and came from a super natural power, they were not hoaxes!
3) EARLY SAINTS AND MARTYRS:
Jesus had his following, those who knew him well and were with him throughout his life and witnessed his death and resurrection and ascension. None of them renounced their faith and they all stood by their word and proclaimed their witness of Jesus Christ until the point of death. I don't know about you, but if I had to endure torture and death, I would probably cave in and say whatever those bullies wanted to hear to get them to stop! The courage to become a martyr (dying for your faith) can only come from a faith so strong, a 100% certainty in what they believed, plus the knowledge of life after death. If many are willing to put their life on the line in order to hold fast to a claim, I am going to listen to what they have to say.
4) FULFILLMENT OF PROPHESIES:
Jesus fullfilled every prophesy from the Old Testament regarding the Christ, Our Saviour.
About Science and Religion:
Now I can't really speak for the Church and there may be some on here who disagree with me, but I think there exists a FALSE DICHOTOMY in mainstream society...that is to say, we are led to believe that Science and Religion cannot coexist. This cannot be true though- Science is how we make sense of the World around us, observe and educate ourselves! For me, the more I learned in science, the more I learned about our PERFECT "Chance", the miracle of life and just how wonderfully us and our world were designed, the more faith I had in a Creator. Personally, it would take more faith for me to think that our World and our life was some accident in a Godless universe! It's just to perfect and beautiful! The more I learned in science, the more I fell in love with God.
How the BIble came about:
It's good to know this stuff too, just so you can have a clearer understanding of WHY we believe what we do. You probably hear a lot that the "Bible is the Word of God!". This one was BIG at the Protestant church I attended growing up and they would pull quotes out of context and be all preachy about it because they were able to find a nice Bible quote. And Catholics also believe that the Bible IS the Word of God, but it's good to know how it came about. God didn't just come down on a cloud one day and hand a Bible to a publishing company. No, the Bible was actually written by Humans! Huh, tell THAT to my protestant preacher... Well anyways, as Catholics we call it the INSPIRED word of God, meaning that it is not without fault having been penned by humans, but that the humans wrote of their accounts with God and Historical events and hopefully were inspired by God in their words. While we are offered many religious truths in the Old Testament, it wasn't intended as a science manuel, not did the authors of the early accounts have ANY understanding of modern science, so the words would have been ones that they would have been able to understand. In the creation stories for example, we should get from it was that God Created the Earth and the Universe with the purpose create a home for his Humans, whom he made in his image. The earth then the fish then the birds then the land animals and finally humans were made. Hmm, this could almost sound similar to evolution in the order of things... We as Christians still use the Old Testament to set the stage for Jesus. Without the Old Testament and the story of Israel and all the Profits Jesus's arrival would not carry the same significance. I am NOT a Biblical scholar, but I would highly recommend taking an Introduction to the Bible Course or talking to a priest.
Like I said, Christianity is very complex but hopefully you are able to make sense of it and continue to build your faith. I hope I was able to clear some things up for you, sorry for the LONG post!
Being a Christian is about following Jesus, taking care of each other and celebrating life! Keep studying science, but don't let people tell you there is no God! They merely have not been blessed with the intellectual ability to fully understand the complexities of Christianity.
God Bless.
Rachel Helen