How do you say this word "sheet"

Macie and I were doing her homework last night and she was practicing reading different words. When we came to sheet she sounded it out and said "shit". Right away she recognized what she had done and we both started laughing so hard. It was so funny. She then said it again for some reason and we talked about why it's not okay to say that word because it is a swear word. She then said but daddy says it all the time. I told Dustin what happened and he told Macie he isn't going to do it anymore. We will see if it lasts. :)