I'm part of the older generation who did get all the childhood diseases. I had them one right after another, with only one ill effect . I developed a hearing problem after the "german"measles. Very minor, but I recall that some children did get much sicker than I did.
But oddest of all, I never got the mumps. And we tried! Our parents would put us together to with kids who had it, sort of slumber parties.
My son did get the vaccines. I wonder what the long term effects will be.
The body gets ill when it needs to basically get cleaned up.
Many people only experience partial symptoms to full exposure of a virus or bacteria. For example, when my daughter had full exposure to chickenpox, she got the fever right on schedule (so many days after exposure) but only developed one or 2 spots that barely looked like chickenpox. I would have never thought that she had chickenpox if I weren't looking for symptoms and knew what day to expect symptoms.
So you probably got full immunity to the mumps, but didn't develop the typical swelling in the jaw area. Maybe you simply felt a bit under the weather.
It is also interesting to note that almost everybody exposed to polio simply gets cold symptoms - a few sniffles.