outside in?

The other day at work I went into the bathroom, when I looked in the mirror I noticed a weird stain on my shirt. When I got back to my box I was talking to a co-worker and decided it would be better to just point out the stain myself and get it over with. I pointed out the stain on my shirt and he looked at it and then paused and looked closer. When he looked closer, I looked closer. He said "I think you shirt is on inside out". I said "I know my shirt is on inside out". I then beat a hasty retreat back to the bathroom where I put my shirt on right side out. As I was walking back to my cube I couldn't help but ask "am I too old to make a mistake like that, or too young". The bonus was that the stain magicaly disappeared when I changed my shirt.