Married so young

How do you all get married so young?? I was raised to go to school, focus on a career and then settle down. But majority of the women seem like they marry after high school. So many people are married at 18, 19, 20, 21. What do you have like arranged marriages or something ? Trained to be a wife ? Do your parents approve ? How do you get married so fast and young ? Why do you do it ? Does it interfere with your life goals ? How do you even get a guy to propose to you so young and be serious ?  You're not scared at all ? So many guys play games and aren't ready? How do you know you're sure ? 
                                                                             
Before anybody else gets offended about the post thinking its condescending. I'm asking because I want to be married and feel like maybe I've done it all wrong. Always thought the love at first sight hing was for movies. Wondering if I've waited too late. I'm wondering what it was like for you. I was engaged at a young age but didn't marry because he left. Now sometimes I think it won't happen.. everybody is married off and I'm still lonely hoping to find this right guy that everybody says will come along that never does. I've met men that haven't been interested in marrying me at all. I was just hoping for insight to see if I made the wrong choices and thinking maybe I missed my chance. Didn't mean to offend anybody by asking what I thought to be valid questions.