I don't know what to tell you except I sympathize! :-(
Ed and I were both 21 when we got married, and while my parents didn't bat an eye (my mom got married when she was 20), Ed's parents were...less than excited about it. We had been in a LDR for almost 4 years when we got married, and here we are...married for almost 5 years now (quite happily too). His family actually boycotted our wedding, which was quite hurtful (his mom came at the last minute, she was the only one) but once we actually went through with it, they seemed to totally accept it and have been nothing but supportive since.
I get a lot of bad reactions when people ask how long I've been married or how old I was when I got married...lots of "OMG you're too young! you're just babies!" etc. And although its quite obvious that I wasn't pregnant (no babies running around!) I did get asked that a lot at the time as well.
Sigh.
You just have to ignore it and let time prove everyone wrong. Marriage doesn't work out for everyone, whether they are married young or at a more mature age and I just have to tell people that I did what made me and my other half happy - we knew exactly what we wanted and went for it.
Ed told me at the time, "Well...I can make my mom happy or I can make US happy."
You can guess what he chose!