My worst up-skirt experience when I was 15 years old

When I was like 15 yrs old, I came from my school, and I was wearing school skirt ( which was up to my knee ).....I did not see anyone at home, then my mom called me to come to the Roof of the house, So I went to the Roof of the house, it was a Rainy and very windy day, as soon as I reached there, a Strong gust of wind blew my skirt up and it Probably exposed my panties to them ( to my mom and dad )...

Watching this, my mom started laughing while seeing at my dad's face as she wanted to see his reaction and she even asked him like " did you see hers "

what did she mean by did you see hers?