My daughter wants her boyfriend to spend the night for her birthday. Should I allow it?

My daughter's 16th birthday is coming up and she said for her birthday she wants to have a slumber party with her boyfriend who's 17 and she said that he would sleep on the floor in her room or even in the guest room if I wanted him to. He has a reputation of being the "bad boy" in school, but he seems very respectful of my daughter and they've been dating exclusively for several months. My daughter is infatuated by him. Should I allow this and under what conditions?