I am a Christian and he is Mormon?

I have a boyfriend whom I have been dating for a little over three months. I am fourteen and he is sixteen. I know I am very young, but I feel the beginnings of love. He is a very devout follower of the LDS church, and until recently, I was not certain in my faith. I realize now that I believe in true Christianity. Although we believe in the same God, our beliefs other than that are vastly different. I talked to my pastor today about that Mormon religion, and I have come to realize that if I want to stay with my boyfriend for a long time, one of us would have to convert willingly to the others religion. If he continues to follow the LDS church and I do not, we would never be married in a temple if we chose to be married many years from now. I have been told that there are also many other complications in an interfaith relationship. I have been pondering what to do about our relationship. I feel like I should stay with him for now, and continue to learn about his religion while still asking him to open his mind to mine. However, sometimes I feel as though it will not be worth my time and devotion. Any thoughts?