Would you let your 19 year old daughter sleep at her boyfriends house?

Im not a parent. Im 19 years old and my mom has given me a no sleeping out of the house rule. Which i am in full agreement to. I dont know call my old fashioned but i just dont think it looks right for me to sleep over my boyfriends. My boyfriend is two years older then me and is in total disagreement with this saying that its childish. Im just curious what other peoples views are.