What if I want to get married and my boyfriend isn't married?

Sydney • Mommy to one baby girl 🎀
I have no idea what to do. We are both 21. I have expressed to him that I want to be married. All I want is to be married at a young age and seeing all these people my age or younger getting married really gets to me. It's like that's what I want soo badly! And a lot of the times the people getting married haven't even dated as long as my boyfriend and I have, for 3 years.
 Ever since I was little I knew I wanted to be married at a young age and thought a would be.
I want to be married like now. He says he's not ready and has basically told me he doesn't want to any time soon. Even within a few years. I really don't want to end it, but I really want to be with someone who is thinking about marriage right now. I don't know what to do and it's so hard. I get really emotional about this subject. 
Has anyone waited to get married when they wanted to a lot sooner? Or had anything similar to this? Or just any advice for me?