Idk what to do about my crush now

So I've had a crush on this girl for a while now but I've been really nervous about it I tried asking for help but it either never worked or never had the confidence and she is giving mixed signals I'm close to just giving up and she's the more quiet time and I'm a loud person idk what to do anymore can someone please help me with getting the confidence and good conversation starters and I have talked to her before sometimes she's more interested then other but usually I get full attention and she laughs at the jokes I make despite me knowing they are not that funny And I gain the courage to tlak to her like once every week and I'm always starting the conversations

Sad news at our school we had a dance but I never gained up the confidence to ask her but well there a couple hours ago I saw her there with someone else can someone tell a good way to get over my crush?