No! I had so much fun in my 20's! I had fun in college, did some amazing backpacking thru Europe, found a great-paying job (not necessarily a fun job -- but I was into money at the time
which allowed more travelling across the US!! Lots of fun memories that bring tons of smiles!!
My 30's were a little harder as we settled down and had kiddies...4 of them!! ...but I wouldn't change much about my 30's either (to date, anyway!) -- still great experiences and awesome memories!!
Now I am starting to think and look forward to what I can achieve in my 40's!!!!!!!!!!
Never look back -- its done and you wouldn't be who you are unless you did the things you did!!