It depends on when you can separate the different types of love. I use to say that I was in love with my best friend in elementary school. But looking back, I think it was a sort-of brotherly love.
I think that the crazy "true love" stuff is when you want to get down and dirty with, live a long life together with, and are willing to put yourself in front of a bullet for your partner, and you feel unwaveringly, unconditionally strong about that. The kind of love where, if you broke-up because you were bad for each other, either you'd try to shoulder all the pain and wish your partner to be happy beyond belief, or you'd try to kill both of you because you'll save your partner the grief...O_O
That kind of passion doesn't come around often, if ever in a person's life. And could be a different kind of love that comes to be in a long lasting relationship.
Because it's so rare for that kind of love to occur, I think it may take an average person until about 25 to become aware of it's existence and actually have a chance to see it in action- through other couples or hopefully one's own self.
But, a different love could strengthen into "true love" in a long lasting relationship. So, I advise you to look at yourself, and see how strongly you feel. You don't have to rush things. You're young and have you're whole lives to be with and love each other. There's a reason why they say "for richer for poorer, in sickness in health." Would you still love him if he got into an accident and was paralyzed/ disfigured? Would you swear off other relationships if he was in a coma? And would he do same? I've seen people this committed to their partners, with tons of love and joy.
Observing family relationships, and my mom's clients, not personal