Shower time

Not a baby shower or a wedding shower....Ella took a shower.  All. By. Herself.  When did she grow up?  How did this happen?  I was sitting on the toilet next to the shower, of course, but she said close that (curtain), mommy.  What???  Why so private all of a sudden?  I put soap on the wash cloth, handed it to her and then she washed herself with the curtain semi-open.  Then I put shampoo in her hands and as I started to help that's when she told me to close the curtain and she no longer needed help.  She even started singing a song in the shower!  She made up her own song, "I am taking a shower" or something like that.  She is so over baths and on to the next stage in life.