Right I'm realy confused?

Basically the girl that I like tried to wake me^^ up at a party after I fell asleep(I was tired not drunk)as soon as I woke up through gut instinct I put her into a rather painful arm grapple(this reaction was brought on by 10 years of martialarts) she started to cry and ran off to her friends before I could apologise. She didn't talk to me^^ for 2 days and completely ignored me. Then last night while out with friends(she wasn't with us) she comes out of nowhere(she was out with her friends and she saw me^^) and punches me^^ in the face...then asks me^^ out...I said yes obviously but I'm confused as to why she would have changed her mind so rapidly. I'm so confuzzled