Any stepmoms out there?

I've got a stepdaughter who just turned four who loves me to pieces and begged me to take a bath with her today and play in the bath so I covered myself and got in the bath with her. I was covered and her father was in there laughing with us enjoying a fun time. My stepdaughters mother found out and posted on Facebook how creepy I am and "fucked up in the head" for taking a bath with her. Am I really that wrong? I'm 20, she's 4. She's been in my life for two years now and even calls me mommy. I love her with all my heart and all I wanted was to make her happy by playing with her in the bath with her Barbies.