I think it has more to do with maturity than age. If you're financially stable, have great health insurance in place, living on your own, have a solid andstable relationship  with your partner and mentally and physically feel prepared, then I really don't see why not. 

You aren't crazy. I am twenty and my boyfriend and I have been together for 3 years. We aren't planning on marriage until we both graduate at least, but we have talked about it and our future together. A few friends of mine ( 4 that I know ) are engaged. So you are not crazy. 

Absolutely not! I started dating my husband when I was 16. I knew then he was the one. Here we are married, 2 kids.... 18 years later :) u know when u know!:)

If you have to ask, then I would say yes, or that you're not ready. 

I'm 20 and I get married in 6 days. You're not crazy :)

When I was 20 I was in a relationship with a guy I wanted to marry. We stayed together for almost 8 years. I am so happy we didn't get married! At 20, the brain isn't finished maturing. That doesn't happen until around 25. Don't rush anything. If he is the one, you will still be happy and compatible in a year or so. Being married isn't the answer to everything. Enjoy your time together and don't stress. ?