I (mostly) agree. I cannot imagine a circumstance under which a 13-year-old who’s engaged in sexual activity that requires contraceptives is engaged in healthy behavior. And I don’t think there are very many progressives at all who’d disagree with me.
I qualified what you said slightly, however, because I remember at that age having peers who were starting to have boyfriends or girlfriends and who were starting to experiment with stuff mildly beyond kissing. I’m not convinced that any sort of experimentation is developmentally inappropriate.