Not sure what I think about my (female) friend anymore

I've been friends with this girl for quite some time (over 5 years). We are 21 years old at this moment and in highschool we took the same bus home and would send each other textmessages till 1:00 am. Skipping ahead quite some time (numerous things have happened, but naming them all would make this a novel). Last year she dumped her old abusive boyfriend and almost immediately had another boyfriend. Her new boyfriend how ever seemed awfully familiar to me. He dresses the same as me, has the same way of doing things, ... the only difference is that he's slightly taller than me and has black hair. I was happy for her, he was way better than her previous boyfriend. While she used to be flirty towards me when she was with her other boyfriend, this had vanished. Now I'm getting the impression that's no longer the case. Her boyfriend now studies in a different city and she's starting to send me more messages than previously again. She also wants to meet me more frequently than other times. At frist I didn't make much of it untill 2 weeks ago. She sent me a textmessage telling me that at some university party she had gotten so drunk she had kissed with another boy. She wasn't going to tell her boyfriend however, because the boy had kissed her. (in my opinion there are always 2 people kissing when it's frenchkissing, but apparently she doesn't share this opinion) Then last week, we were sending eachother textmessages and were just talking, I made some comment about biting to which she responded that sometimes biting is horny. Just trying not to make the conversation too awkward I replied by: "yeah, I know". She was under the impression I was still a virgin, which I'm not. Just didn't tell everyone as I wasn't that proud about it. So she started asking about it (how it happened, how many times and strangely enough if it was safe). This is my first issue, I know she's curious about everything, but is this just curiosity or is there an ulterior motive? I explained her how and why I had some onenightstands and in the explanation mentioned having a crush on her several year ago when I only just knew her. She then answerred with telling me she was more at ease now she knew I wasn't a virgin anymore, because she wasn't sure if she could make comments about it before(so far not that strange). Then she added that she was more comfortable aswell to visit me in the city I study at and stay for the night, because now she wouldn't feel that guilty if she became drunk and would kiss me. Is it just me, or is this something you would only say if you had already thought about it, thought it had a high chance of happening or even want it to happen? Then for the last part. She asked if I was going on a holiday after my exams in January. I told her I was going with my family, but had a double room all for myself. She then asked if there was a possibility for her to come along. When asked if she wasn't going with her boyfriend she responded by telling me she would ecplain it to me when she was feeling up to it. At that point apparently sharing a room wasn't a problem for her what so ever. Then she didn't say anything anymore for 2 days. Now today she isn't so keen on going along on the holiday anymore, not because she doesn't want to, but beacuse it may look strange towards her and my parents. Something I thought 2 days ago. No she's suddenly thinking about going with her boyfriend to somewhere. Am I overthinking this all, or am I right that this isn't really a normal situation? What do you think about this? I don't really know how to approach this problem, should I ask her to talk to eachother to find out, ignore her, jut let it go and act as usual,...? I do like her, I did have a crush on her years ago, but at this moment I just don't know what to think of her. She apparently has no problem with cheating on her boyfriend. At some moments I genuinely hate her, but that just seems to fade away after a few days. (I can't stay mad at anyone) Advice is very much appreciated