How to Know if a Girlfriend Wants to Have Sex

Ask her. Approaching the topic of sex and openly discussing sex, can be a difficult thing to do. It is important to realize though that if you are not mature enough to talk about sex, you are probably not mature enough to participate it in yet. The most direct way to find out if your girlfriend wants to have sex is to ask her.
Step 2
Watch her body language. If your girlfriend wants to have sex she is most likely sending you signals through her body language. If she is getting closer to you than she has in the past and touching you in ways or spots that she never touched before, she might be interested in sex. Be careful though, she might only be looking for more intimacy and cuddling, but not sex.
Step 3
Advance to the next step and pay attention to how she responds. If so far in your relationship, all contact has been on top of clothing, try moving your hand under her clothing. If she likes that and does not try to stop you, slowly proceed or wait until your next makeout session if you worry about rushing her. Continue advancing to the next step until her body language or her words tell you that she has had enough.
Step 4
Stop when she tells you to. If your girlfriend says no to sex, then she means no. Trying to have sex with someone who has said no is illegal and is considered attempted rape. Succeeding in having sex with someone who says no is rape and you can be prosecuted.