It's not that it's so bad to get married young, but there's no particular reason in favor of it now. social norms have changed a lot, you can live together and all that. the thing is you really don't understand at 19 how different you will be when you're even ten or fifteen years older. I met my husband at 21, now I'm 33 and I am really just a completely different person now than I was then.

People are always going to change no matter what age they are when they meet, but it's more extreme when you're younger. Even a little more life experience will tell you if the changes are likely to be compatible.