>>509906942 (OP)>consentThere is no answer. 18 is actually pushing it, a high schooler does not know what the fuck she's getting into. Realistically 14-16 year olds have sex with adults all the time, it is incredibly normal at least in America. Me personally I've known many girls in my middle school who fucked college boys/one who regularly flirted with the teacher and sat on his lap and he did nothing but blush.
But from a legal standpoint yeah until you're at least 20 you're objectively an irresponsible fucking idiot and any sexual decision you make has a 90% chance of fucking up your life. This is why stable minded individuals always have sex without a condom in their early 20s, while the children of failed or dysfunctional families always have very young parents.