Because of my age, I may have received a not-so-effective-now MMR vax as a kid. So, I reached out to my doc and asked about it. He suggested (and I agreed) to test to see if I have immunity; if I don't, vax me, Baby!
Btw, last time I had a similar test--to see if I'd had chickenpox and thus need the shingles vax, turns out I never had the virus (my mom lied, a lot, including about that).
Long way of saying, if you don't *know* your immunity status, get checked.