Is it a thing to....

Get married right after high school? I graduated in 2016 and pretty much the majority of people who didn't enlist or go to college are either married or having babies or both. There are a few who got married and go to college and a good bit who enlisted and got married as well. Like is this a thing? You literally just started being an adult and now you wanna be tied down in something that will probably end with divorce? Like a lot of them work in restaurants or some crappy blue collar job and their probably never gonna leave the area they were born and grew up in. And why do their parents just let this happen with no objections? I mean I'd say probably around 75% of people I graduated with had divorced parents, that might be a tad high but I was definitely in the minority for parents that were still together. But honestly though is this a thing everywhere in the United States? If it then why? Why get married and have kids so early in life? These kids literally like 18,19, or 20.