I am a lover of girls roughly 12 and up... Of course, I am on BoyChat as well, with a similar AoA for boys as with girls. Really, it is the breasts which trigger attraction. More than any other factor, the presence of breasts change my attitude from one of indifference to attraction... With boys, on the other hand, there is no one trait that has this effect; it's more nuanced.
Why do I like young girls? I like their smooth noetonous faces; their petite, but shapely bodies; the glow of their skin, which seems to be lost as a girl enters her late teens... I like the long smooth legs, longer in proportion to total height than fully developed women...
But it's not my fault, my ancestors gave me this!