When people say I look too young to work. This may seem like a compliment, but when you look young in your 20's little things like this are really frustrating. What they're basically saying is you look like you belong in high school or at home playing PlayStation. Not doing adult stuff like working.
Take it as a compliment. Your young looks will perhaps pay off in the long run - you'll be 40 and won't have to look like a decrepit old burlap sack. If you want to be an asshole, politely and on-the-daily remind your coworkers that they are old and are going to die before you. It will really demoralize them and put you in a position of superiority.