How to treat a 20-year-old who can't ride a bike?

I think it may be that you haven't been exposed to bicycles since you were a child, or that the school you went to as a child is near or far away. Or afraid of wrestling. (It's just my own guess)

Because I didn't deal with bicycles when I was a child, with the growth of my age, I gradually found that I couldn't ride a bicycle and became the laughing stock of others. I want to study, but I'm afraid of being laughed at while studying. When I was 20 years old, I still couldn't ride a bike.

This should be a sign of lack of confidence. Don't care too much about what others think of you, and make your own decisions.