AITAH for screaming at my stepdaughter?

I (27 F) have a husband (29 M) who has a 9 year old daughter from his previous relationship. We both look after her, and I do everything a mother should do for her child, because Ivy’s (my stepdaughter’s) mother abandoned my husband and her when Ivy was 3. I try my best to be a good mom for her, but my stepdaughter doesn’t listen to me at all. My husband says she’s just a child and it’s fine, but I feel really disrespected. Last time when I picked Ivy up from school, she loudly called me a b*tch In front of her friends to show them that I won’t do anything about it. My last straw was when today she refused to go to school and threw a slipper at me. I got really mad and started yelling at her, and pointing out her outrageous behaviour. Ivy started crying and later my husband came up to me and started an argument about how she’s just a child and she didn’t want to make me mad. I left the apartment to take some time for myself, and now I’m sitting in a cafe and writing this post. So I don’t know, am I really overreacting? Or are they the ones in the wrong?