I wasn't allowed at his house until we had been dating for two years. I was never disrespected by him or taken advantage of Hope this helps.I started dating my boyfriend when I was 16 and he was 19.The best thing to do is show you support her but also are just worried.
My parents told me that I couldnt date a guy that was older than me and I continued to see him behind their backs.
My mom had issues with it at first with the whole age thing, but once she got to know him she was okay with it.
It took a little while, but now she views him as her second son and we plan on getting married after we both graduate college.
They're young and gaining experience in the world, learning about how people and relationships work.
Just do what you, be her mother; be there for her, teach her what you know, and be her support.
You may find that he is not at all what you thought and he is far less likely to do something "wrong" if he knows who you are, and what your expectations of him as a friend of your daughter.