My parents were 19 when they married, it will be 49 years this year!
I was 24, DH was 25 and we were some of the last of our "crowd" to get married. I'd been out of college for a few years and was supporting myself, DH had gone back for his masters but was also working and supporting himself. We didn't feel young at all. We are hitting 13 amazing yrs this summer.
The argument that drives me crazy about people marrying young is "you need to go out and have a chance to experience life before you settle down." There is nothing I would rather do than experience all kinds of things with my Husband. Just because we got married, doesn't mean we stopped doing things, learning and growing - we just get to do it together!