Is it okay for my 18and 19-year-old stepdaughters to see me naked and fully erect? They both stare at my penis and know that it

Actually, my step daughter surprised me! She had come to my house to spend the weekend and do some horseback riding. I was in the shower and not paying any attention. I stepped out of the shower, there was my step daughter sitting there with a smile on her face. She merely said “oh I am going to have fun this weekend". I'm sure you can figure the rest out!!