My cousins girl is a mega hottie (HB8) and he's a super beta. Just watching the dynamic of the relationship I can tell she's cheated on him multiple times already. I'm calling it off limits because that's my cousins girl, despite her being very feminine and submissive to me in general.

Anyway, one night I'm over at their place and she brings a friend over. We're watching the new Game of Thrones and her friend is just laughing at everything I say and is clearly trying to get my attention. They both are. Whether cousin's girl intentionally set it up, who knows. I get the new girl's snap and hit her up 3 days later saying
"Let's grab a drink this Saturday?"
"I work :p"
"Some other time then"
She says some nice message saying thanks for the invite though

Later she says
"Did you mean as friends or a date? Lol"
"Labels spoil the fun. But not as friends" (Maybe this is cringe or whatever idk)
"I don't think that's gonna work bc I have a bf lol"
"Don't see what that has to do with me"
"Well I'm flattered but I'll pass. Maybe I'll see you around though"

Intending to simply wait it out until her current bf displays more beta behaviors and her hamster wheel starts spinning, but what could I have done differently?