Is my friend's relationship moving too quickly?

It sounds like the pace is okay for right now. Like other posters have said, you cannot become overly involved in her relationship but you can look out for her if you really think they're being wreckless. Teens engaging in ual activity for the first time is a whole different can of worms so if she mentions that to you, you should suggest she do a lot of personal reflection, medical research, and maybe also some discussion with a responsible adult. Otherwise, all you can do now is let her enjoy her new relationship.