Is it normal my sister kissed me while she was drunk?

Last night, my sister who's a bit of a lightweight ended up getting really drunk and tried to make out with me. She came into my room without a shirt, which I didn't think anything of because the weather here is still pretty hot. At first I let her kiss me because I thought it was just going to be a quick, friendly kiss but I realized something was wrong when she got really into it and didn't stop immediately. I got her off and saw she had kind of a blank look on her face, I don't know if it was because she realized she had done something wrong or was just out of it. I told her to get some rest and she nodded ... then fell asleep in my bed so I slept on the couch. Sigh. The next morning she came to me in tears and begged me to forget about what happened. She gave some explanation and kept saying sorry, and I told her it was okay, I would just pretend it never happened. Really though, I feel really awkward about it happening. I'm worried that there might be something wrong with her, and she feels terrible about it.