I have three girls who, in various ways, claimed the title of my "first love".
There was the girl I dated from age 11 through 13, although "dated" might be a strong word indeed---we were just about inseparable, a true case of puppy love, and she's still one of my best friends 20 years later. Keep in mind I grew up before MTV invented hypersexualized childhood, so that accounts for getting all the way into the early stages of puberty without someone expecting me to fuck the girl.
Then there was the girl I loved at 16-17 and to whom I lost my virginity. That was high school love, the kind of love where you think you're going to live forever after and have a bunch of babies (and considering our lack of dedication to common sexual sense it's a wonder we didn't---the gods must clearly be watching over me)...and we broke up after being together for a total of seven months as we just kind of outgrew each other. Oh well...at least it got me on the board.
And then there was my first real, adult, grown-up, honest-to-gods, capital letters LOVE, at age 20. I loved her then---13 years later I still love her, and I always will. Our relationship ended because she literally descended into madness. Schizophrenia, DSM-IV genuine psychiatrist diagnosis schizophrenia. And watching her slip away from me...I've dedicated the "Forever Rachel" song from Final Fantasy VI to her. I hope she's OK. I haven't seen her since everything went down.