Meeting the family

Im Meeting my boyfriends family for the first time tomarrow, and I don't know what to wear or do with my hair. Any ideas???
His mom is kinda up tight and their really into church. I don't know if I should get all dressed up, or if I shouldnt.
We're...

going to applebees for dinner then me and him are going to a movie after.
Help please?

ok ok calm down
dont dress up to much
but dont dress down maybe just
wear something that doesnt show to much boobs
and dont wear normal clothes
just wear something nice
but not to fancy

I met my bfs parents in sweats
cus I just came from a swim meet
the dad was looking at me but then finally didnt care
cus I had a nice shirt on
but ya

dont worry I was freakd but then
finally calmed down

I don't have a lot of time to write but I would have to say my best pice of advice is not to show a lot of affection towarge each other dont kiss or w.e infront of his mom exspcially and maybe even not hold hands unless he pushes it