I was about 5-7 years old when I was found out by Mom. Thankfully I was not caught in the act of wearing her panties and half slips but, somehow she knew. Likely my crappy refolding skills I'm guessing. She was very kind in her explanation that little boys shouldn't wear ladies clothes and left it at that. I'm pretty sure that she didn't really know what to say or how to deal with it but my over riding memory of the conversation was that she was kind and understanding.
She has just turned 90 and I am now her principal caregiver. As an homage to her, every time we visit. I wear panties. In her honour, more or less.
I don't know how to explain it other than I think it brings us closer, in an unspoken sort of way...