Nothing, your guilt is response to the socially constructed moral codes you've been conditioned to follow since your childhood by your society which can't really resist your own biological instincts of being attracted to sexually mature females of opposite gender(And females are the most fertile during late adolescence and start losing their fertility once they hit adulthood and old and busted by the time they reach mid 20s, an age which most women start having stable careers and decides to have kids these days).
Just a century ago, the age of consent was just 12. Your average male married immediately after he got a stable income, that's somewhere around 18 - 20 and usually married a woman 5 to 6 years younger than him. Even sexualizing teems wasn't a big deal few decades ago as ssen by many old movies such as Romeo and Juliet. But come expansion of corporate work culture and participation of women in the workforce, as well as involvement of the feminist nexus, eventually whitoids became conditioned to believe being attracted to teenagers is something weird.