“I hate lying to my mom about my feelings”

I’m an 18 year old guy who lives with his mom (no dad.) I’ve been confused about my gender. Earlier today, my mom came home from the store with a big bag of women’s underwear she got on sale, so I stole a pack of them to try on, and now I’m worried she’s going to find out somehow. She seems open minded as I’ve already came out as bisexual, but I don’t know how she would handle this. On top of that, I feel bad for stealing them. What should I do?