Aww, good luck on the date. Just have fun and be yourself.
On the movie choice, yeah, I don't know if horror movies are the best idea. I mean, it's not bad for everyone, though as someone who hates horror movies, I wouldn't be too thrilled about it, tbh. Then again, my Dad took my mother to see the "Texas Chainsaw Massacre" movie on one of their first dates (I believe it was their first) and they got married with kids. You never know. It's more about the individual than anything. What she's like and all. Do you think she'd be into it? Do you know if she likes horror films? Anything that might give you a clue?