Parent advice teen dating
She needs to prove to you and herself that what you think, is of no concern to her - but it is a ruse - it matters more than she can accept or let on.
If you are not condemning (and sounds like you are not) but instead acknowledge the fact that this is ultimately a choice she must make about her own body, she will be more able to hear the things that you want to say about the situation.
I want to support her to start thinking through some of this for herself, but whereas she used to have very good judgment, these days she's running on low self esteem and hormones and I believe would follow anybody home who told her she had beautiful eyes. I talked to her about birth control and safe sex and she clearly was not ready. She went to his house once or twice, all when parents were home. When she has been out later with others I often pick her up (the joys of cell phones! I guess when there is another boyfriend I will want to meet him also.
The most important thing you can do (and obviously already are) is to be involved, and concerned.
That does not mean, that if you think she is too young that you need to hide that opinion, but present it in a way that acknowledges her ability to make different decisions, and make sure it conveys your concerns about the effects her choices may have on her rather than an issue of right or wrong.