Any tips on how not to get scammed?

Me

Hey y’all I have an Apple Watch that I’m selling. I put it on Facebook market place and got tons of responses. I talked to one girl said she wanted to meet tomorrow then said that her roommate would be the one meeting me. I don’t know why but I feel a little put off by that and I’m wondering if I should go with someone else. I’ve never sold an electronic item and I’m really worried about getting scammed