I've been researching a similar question: I had red measles as a child, about 7 or 8 years old. Do I need the vaccine?Can one get the measles if they've been vaccinated?
Everything I've found says, "No. You're immune."
Of course, there are rare cases of re-infection even among people who've already had it. But the consensus is if you've already had measles, you're good for life.
The word on having had the vaccine is close, but not quite that strong. If you were vaccinated before 1967, or work in public-facing healthcare, or are immuno-compromised, or planning to travel internationally (especially to developing countries), you might want to consider a booster.
Side note: Even at that young age, I still remember how miserable I felt for what seemed like an eternity. Missed a week of school, and I rarely missed school at all. That would have been 1966 or 67, and I'm not sure if I was vaccinated. Probably not.
The Basket Cases are going across the pond in the next few months, and we both plan to get a COVID booster about 3 weeks ahead of 8 hours in the germ tube.