Adults sign up for beginner swim lessons all the time. Most people who notice are quietly cheering them on.

Being a visible beginner at an age when you are supposed to know already is the main thing that stops people learning. The imagined audience is harsher than the real one; those who notice have mostly been the oldest beginner somewhere themselves and are quietly on your side. The embarrassment is real and it is also short.

Book the thing you have been avoiding because you should have learned it years ago. Swimming, driving, reading music, basic maths. Choose a class full of adults and let the first session be as awkward as it needs to be.