An excuse to not go..

I got invited to a party on Friday by some really nice people I just met. I'm new to the area so they invited me and even offered to pay...for some reason, I just don't want to go. It doesn't seem like "my scene" but I'm terrible at saying no. What's a good excuse? 😁 I know, this is so stupid but I'm a really shy girl, not outgoing at all and I just feel like I would be uncomfortable there..or I would be left out.