Can I see Mom?

Today, I had a shower while Timmy was playing with his cars.
Suddenly, he opened the bathroom door, while I was washing my face.
Tim: "What are you doing Mom? Washing your face ya?"
Me: "Yup.   Please close the door Tim."

Then he went away and played with his cars again.
Not long after, he came back, stood in front of the door and said: "Mom, can I see you while you are having a shower?"
Me: "No Tim."
Tim: "Why Mom? I want to learn how to have a shower by myself."
Me: "Let Papa teach you  on how to have a shower by yourself."

He then went off and played again, only to come back not long after that.
By then, I have finished my shower and he asked me again: "Mom, why I am not allowed to see when you are showering? I am not a stranger."

Oh dear, I don't know how to answer this one....