I'm 33 and completely exposed to MMR, since my antibodies have all worn off. I would love to get the shot again, but I had a severe reaction as a child to it (paralyzed, GBS type stuff), and can no longer receive it.
So long as you had no allergic reaction the first time you received it, go ahead and get it, they are very safe. And I'll be envious that you don't have to worry about getting M,M, or R!