Getting engaged

I've seen a few people saying that they're engaged really young (like 17). I was wondering what time you got into your first engagement (whether it led to marriage or not), and why you got engaged at that age, particularly if you're still "young".

I don't think it's commonplace for people to get engaged / married in their late teens or early twenties where I live, so it just seems surprising the number on here.

(I'm not judging, I'm just curious as to why.)