Hey again TRP, I once again find myself in need of guidance for a situation I'm not so sure on how to approach.

I'll keep it short n simple. For reference I'm a HS senior. There's a girl I know who is really cute, 8/10, and I didn't have much interest in her until recently. I'd occasionally talk to her but not in a friend, emotional tampon kind of way. She's invited me to a party she's throwing at her house. Unfortunately, she's also invited my sibling, who tends to act as a cockblock because we don't get along very well... Thing is, is this a sign of interest? How could I escalate the situation?