She thought i was cheating on my girlfriend but she didn't care iin?

Quick back story. A few weeks ago I broke up with this girl Nikky I'd been dating for a long time and since then I've gone out on a date with this one girl, and took another back to my room after smoking weed(though nothing happened unfortunately)

Anyways the other day I was at my school cafeteria chatting to this girl I know about the two girls I tried to get with recently and near the end of the chat she was like, ''wait are you dating Nikky?'' and I told her no we broke up a couple weeks ago, at this point(I swear I've never seen such a strong reaction from her before) her eyes looked liked they popped out of her head and she's like,''YOU DID?, wow, when I see her I don't even think, Nikky, I just think oh there's (my name's) girlfriend.''

I didn't think about it at first but then I asked her, ''wait, you thought I was still dating Nikky while I was telling you about these other girl's I was trying to get with?'' she responding by saying ,'' well lots of guys do that.'' I replied back, ''I've never cheated on any girl I've ever dated. And If I was, do you think I'd just casually tell people?'' to which she said,'' I wouldn't tell her, I don't like Nikky.''

Is any of this Normal?