Oh wow. "Last night we practiced some petting"! You are doing it wrong. You should both be driven together by passion, charged with animal LUST, and you should both be so fucking hungry for eachother you neither care nor worry about, this thing called sex, you are just doing what you want and feel to eachother. In that state you can't really do the wrong thing, you don't need to touch her "special places" or wtf ever, she'd be one big walking, special place and so would you.

Also it helps if you both love eachother? Doesn't sound like it to me. You worry to much, she seems, uh. Do you btw know how much your premature tampering with sexuality has fucked up your first true experience? With all these expectations and fears, things you don't need to know, things you shouldn't know. And her not being a virgin is also teh fuck for similar reasons. She will compare you to all her previous experiences, you already know that. Perhaps if she loved you so much that her past has been totally washed away and she's like a virgin anew, but it doesn't sound like it to me. If at least she loved you in that way you would definately not sit here sharing your concerns about a bad petting experience.