Should I let her go?

So my daughter will be 16 this August. She has been dating her bf for almost a year now. They are both honor roll students and really good kids. He hangs out with our family and she hangs out with his. My daughter is very trust worthy and she is overall a good kid. Now his family is going to Myrtle beach this summer. (We live in Ohio). They invited her to go. Now I know his parents fairly well and they are good people. I actually worked at the same hospital as his mom before I resigned. I already told her my worries about sleeping arrangements and that I would be talking to his parents extensively about this. I want to let her go but it still makes me nervous. Any advice or insight on this would be helpful. Thank you.