I think you need to take a two steps forward, one step back approach. Make out. Then, without trying to cross any new borders, just stop and do something else. Get out the checkers board. Pull out a book of Madlibs. When she asks what's up, you can say you just feel like hanging out with her today, but not anything else. Her brain will turn inside out trying to figure this one out. The idea you want to get across to her is you're not just hanging out with her for sex. Then, after a while, if the vibe is right, maybe give her a kiss. Nothing more. Back to business. Then after a while, maybe a hug. In other words, keep the kino going. This will give you feedback. If she responds, go for it . . . for a while, then pull back again.
Keep this up and she will very likely tear your clothes off and take you to Mars and back.
Communicate non-verbally that you aren't just into her for sex (even if you are). And when things progress, you be the one to slow things down. You are controlling the pace, not her, but starting and stopping at your whim.
Good luck.