Teenage girls (when I was a teen of course or until my mid 20s for 18/19 year olds).
Now (for the ones that are legal) it's like "Just shut up unless you want to fuck. You are annoying, immature, and we have nothing in common."
But honestly having just turned 30 I'd feel kind of weird fucking any girl that is legal that is under 21. Like, of course I'd still do it... I'd just feel a little dirty old manish now afterwards lol.