I was the same way. I never got a flu shot, never got sick, etc.. until the age of 60, I had not visited a doctor more than a half dozen times in my life.
That being said, I started getting my flu shots, vaccines, etc at about 65 and maintain them every year.
Why? First off, just as our body becomes weaker as we age, so does our immune system. Pneumonia is difficult fir a young person, but the survival rate drops with every decade.
Covid, the flu, etc all have similar statistics.
Every one of my doctor's have told me to get and keep all my vaccines up to date.

I only have two colds a year and they last about four days. I have had the flu only a few times in my life and I am 68 years old. My PCP recommended the pneumonia vaccine that is one time for life and I have done that. I will not have any flu shots for I have never had a flu shot and I am doing fine. It’s the Parkinson’s and vertigo that are my main issues.

My neurologist just asked me if I got them and I said no and had no intention of getting them because I rarely get sick and only hat the flu a few times in my life and it was years ago.

I've gotten the covid and RSV vaccines with no ill effects. I just have the flu vaccine too go.. I've always gotten this vaccine to and don't anticipate any issues.

My neurologist just asked me if I had the vaccines and I said no and have no intention of ever getting them and she just said okay. After all, it is my choice.