Sometimes you should just stop thinking and ask.... What's the worse that could happen? She'd say "no I don't wanna dance with you"... Or maybe she'd say something so rude that you'd become sad for days...( I don't think she'd be so rude to you, there's no valid reason)... And you'd feel sad, and broken, and maybe lose a 'friend'... What else? And on the other hand you could learn how to break your own boundaries and how to overcome social anxiety. And maybe you could learn how to deal with rejection!! I'm not a very social guy but trust me, I tried this and still try things like these. I was anxious and neurotic as hell some years ago. Even today, I'd tremble inside in some situations. But pushing yourself sometimes... It helps, really!!