Fashion advice

I don't normally wear anything shorter than walking shorts in the summertime because I don't like my thighs, but today I purchased some shorts for the Fun Run we are participating in. I put on all of my running gear to show my children, and this is the response I got:

Me: What do you think?

C: Mom. Those shorts are kinda inappropriate for someone your age.

Me: C, women my age wear shorts this length all the time. I just haven't ever worn them because I don't like the way I look in them.

C: Oh. Well then, you look fine.