Finding out about my dad's secretary.

My dad's away for a week and his secretary is going to stay for a week. My dad's secretary is in her forties she's really pretty with long brown hair she's almost 6' tall and most of the time she likes to wear really short skirts. It was a couple days in to her stay at our place and it was early morning and I had to go piss. I didn't know that Erin was in the bathroom and I walked in as she was getting out of the shower and she didn't hear or notice me going in the bathroom. The mirror was big and the mirror was positioned in a way that I could see Erin coming out of the shower. I was taken back when I saw that Erin's got a cock and suddenly my cock got really hard and I was kinda liking that my cock was hard because of seeing Erin's cock.