take it slow man if she ever visits your place, leave a porn magazine out in a room her parents won't venture into, and if you have a tv in a room you know she will visit, have a porn video playing with the volume down. You can always pass that off as accidental exposure. she may get curious after that. Then you have to worry about birth control condoms and all that shit.
she is 13. girls 12 13 and 14 are really curious about what it feels like to have sex. most want to fuck a MAN with a large dick. after they have fucked both a boy and a man, the man wins every time. i have fucked a tiny 10yo who could only take about half my 8 inches. by the time she was 13, she was taking it all. i have had 6 12yo 9 13yo, and at least 25 14yo. go for it.