TIFU by accidentally impersonating a blind person

So this actually happened a month or so ago, but I remembered it today.
We were on our way to the waterpark with our daughter when I stopped by Walmart to get some fold up chairs to bring with us. I couldn’t find them. I found a family around the camping gear and asked if they had seen any. The woman told me they were at the end of the aisle. I still didn’t see them, and she pointed. When I finally found them, I turned to her and jokingly said, “sorry, I’m blind”
Her face dropped. ATP I realized I’m wearing a big T-shirt with holes in it over my swim suit, and sun glasses. I turned and went to get the chairs pretty quickly, and I stupidly accidently knocked them over. When I went to pick the up, the husband asked if I needed help.
I said, ” yes please,” because they kept falling.
When I was well and embarrassed, I turned to leave and thanked the people behind them thinking they were the family, only to realize they were a older couple.

My father is blind and walks with a stick. I would never do this on purpose.

TL;DR: I accidentally told someone I was blind as a joke, but it didn’t come off that way. And then I embarrassed myself by doing things that made me actually seem blind.