Help! How do I act when meeting my favorite band (paramore)?

I am going to my first paramore concert in september. I have floor seats and I am going backstage. Hayley Williams is by second cousin by marriage because my stepdad is her cousin. I kinda want to know how i should act. I know that i should act myself but i do not want to freeze up or anything. like getting starstruck haha. but i am so cluless on how theyre meet and greets work? anyways what should i say? my stepdad is going to be theyre so at least she will know him but. Im just super stoked and really nervous! HELP