Flirting

Why would she say this to me if she’s not lesbian?

This girl can be sexual at times. She’s not outwardly or open sexual, she’s really mature and calm but I know she has that side to her when she gets drunk and goes out. She’s had hookups before but at work she is very like by the book and takes her job seriously. Anyways, there might be some kind of flirting going on because we’re both young. I’m always smirking when I tease her and she’ll pretend to get offended then tease me right back eventually. Once she touched my arm after doing it and laughing. It’s not hurtful teasing of course.

I wanted to tease her one day and she was singing and I I told her to stop because she’s annoying and can’t sing. Then she was like “I’m gonna come over. I’m gonna come over to your place late at night and sing you to sleep” then I said “oh my gosh” and smiled because I felt a vibe and she laughed. was this sexual given our flirting-ish history?
Why would she say this to me if she’s not lesbian?
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