well i had my first love when i was 10! although in all honesty, even i believe i was too young, well i know i was personally.
Thing is, unfortunatley, love will hurt you back, its as predictable as gravity. And at 13, it will happen. Its unfortunate. I should imagine the same will happen to you what happened to me.
Circumstance that are out of your hands with change things. I dunno, your parents more, she moves school, even different classes make a difference. Or she goes on holiday meets someone else, theres a million different things that can happen. For me...she moved, and i was devestated!
Regardless of all the bad stuff that can happen with love, theres a million and one good things that can also happen. All these experiences take time to understand and learn from. Even for the likes of us adults mate!
The choice you make now, is entirley yours. You can carry on loving her and being boyfriend and girlfriend theres nothing wrong with that. All im saying is, try not to be blinded by the belief that she'll be your one and only love.
Above all though, dont wish yourself older than you are. Believe me, youll turn 30, and wish you were 13 again!