moms of boys

Ok I'm a newbie here but this is kind of embarrasing but was wondering if this has ever happened to anyone else?

I was heading out the door when I remember that I forgot a sheet set (for my sister) and went back into the house. I began to walk up the stairs and noticed that the bathroom door was open and my 18 y.o. Alex was standing in the bathroom naked (he must have thought I already left and was getting ready for the shower). He didn't see me(phew thank goodness!)

But my reaction was what concerned me. At first I thought, oh geesh Alex you're naked hon. As soon as I realized that it's like my eyes went RIGHT to his penis and I did stare at it for a few seconds.

Now I'm wondering if any other mom of boys have this reaction when you see him in his birthday suit, is this normal?....I am embarrased