Point of a relationship?

I'm a 20 year old guy dating an 18 year old girl I've known since childhood. I wouldn't say that I'm in love with her just yet, I suppose she does, but I do care for her a lot.

Whats been holding me back from starting a real relationship with her is just this: whats the point? All relationships between people our age end up badly, and I don't want to lose her. I guess part of me doesn't want it to end if we do hit it off. I don't know its like society dictates it, like its saying "you're gonna waste your life and miss out on all the benefits of single life if you end up in a relationship."

We can become bored of each other in later years because we hooked up at a such an early age. I know for a fact that she wants to "save" me for something extremely serious (we have a lot of history and experiences together).

So my friends, whats the point of college relationships if they all end badly and almost never last?

PS: this question sounded a lot easier in my mind hehe.