Am I the asshole for not wanting to go to my graduation ball?

Hi, I’m a sixteen-year-old girl. When I was younger, I lived with my dad and stepmom, but then my dad went overseas for work, and my stepmom followed him. I had to move in with my mom, stepdad, and younger half-sister.

My graduation pictures are coming up in a couple of days, and I've been wanting a silk press for my hair. However, my mother said no to getting a silk press because it was too expensive, especially since my sister was also graduating.

My stepmom and dad offered to pay for it, but since it was around $82, they ultimately didn’t go through with it. While my mom and I were discussing more affordable hair options, the topic of the graduation ball came up.

I told my mom that I didn’t want to go, and before she could ask why, she assumed it was because my friends weren’t going. I repeatedly explained that I just didn’t want to go, but I didn’t have specific reasons for my feelings. She began crying, begging, and gaslighting me about it, saying how she didn’t get to go to her own graduation ball, and that she wanted me to go.

What hurt was that she wouldn’t pay for my $82 silk press, yet she wanted to spend on something I didn’t want to do, which would cost $113. On top of the ticket, I would also have to pay for my hair, dress, car rental, lashes, nails, accessories, shoes, and makeup.

Eventually, I couldn’t handle her crying and pleading anymore, so I reluctantly agreed to go. I feel like she’s struggling with my choice because her father didn’t let her experience many things, and she seems to disagree with everything I say.

Even for my graduation pictures, she showed me a hairstyle I didn’t like. When I mentioned that I preferred something else, she ignored my choice and kept looking for new hairstyles. It feels like she doesn’t want to support anything I like or want to do.

So, am I the asshole for not wanting to go to my graduation ball?