Excellent question.
I for one have an extremely strong preference for girls in early adolescence (11-14), which makes me a pretty typical hebephile. This preference applies primarily to physical appearance, but I am also attracted to archetypal childlike personality traits such as innocence (
not implying asexuality!), curiosity, a sense of wonder, candor, simplicity, untainted authenticity, playfulness, a fun-oriented outlook on life, and a non-judgmental attitude towards others.
That said, I have been very attracted to some girls as young as 7-8, essentially ones with a more preteen-like body and a mind demonstrating an outstanding level of maturity. I need to be able to have coherent and interesting conversations with a girl if I am to truly love her.
Conversely, I have been in love with one adult girlfriend until our relationship broke down when she was 27. I can be attracted to a few rare adult girls, generally in their late teens to 20s, but up to 30s would be quite plausible (and even later is conceivable, especially with advances in cosmetic surgery and anti-aging medicine), provided that they are physically petite and cute, have the corresponding aesthetic sense in the way they embody femininity, and display the aforementioned core personality traits that usually characterize little girls. I have found that such a personality often persists beyond childhood in girls blessed with a genuinely happy life until then.
Most importantly perhaps, any adult girl I connect with sexually pretty much necessarily has to be an
autopedophile with fantasies that are sufficiently symmetric to my own (primarily with respect to age-of-attraction, but also sexual roles, aesthetics, etc.). An easy way to determine whether or not that's the case is to show her some lolicon, and/or have her read appropriately transgressive erotica, and see if what turns her on is also what turns me on.
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Lolicon importantly being, according to Wikipedia, a form of erotic fiction whose legality may vary throughout countries our forum serves - Mods]