So I went to this party at this popular girl’s house and apparently her best friend has a huge crush on me. Near the end of the party the girl who owns the house said that she needed supplies in one of the bedrooms and her best friend went with me to get it. When we entered the bedroom the door was locked behind us. So we were stuck there for the rest of the night. She seemed really excited by that and she suggested since we were going to be alone together we should get intimate. Well we ended up having sex and spent the night together. We also had brunch the next morning the girl who owns the house and her boyfriend. Anyway we exchanged phone numbers and she’s texting me as if we are a thing. She wants us to spend the week at her friends house because her parents aren’t there and we’d have our own bedroom and that we should go see a movie tomorrow and a nice dinner. How do I tell her we’re not a thing and to slow things down?