A woman on Reddit is upset that her mom went behind her back and gave her younger sister her old prom dress after she said no.

The 25-year-old explained she bought her own "dream" prom dress when she was in high school after saving up for an entire year.

"I had an amazing time and that dress is very important to me since I have never had the best self confidence and it made me feel beautiful. My sister (let's call her Annie) is having her prom later this year and she asked if she could use my dress as well," she shared.

"I told her that I would prefer if she didn't since it is so important to me (I also have a neuro disorder and it makes it hard for me to let other people use my things) and she said okay and said she at least wanted to ask, but she was fine with finding another dress and I said I'd help pay if she wanted (and if she wanted, she was welcome to use the jewelry, she will wear the hair accessories)," the woman continued.

Her sister thanked her and they agreed to go shopping together. However, when the woman visited her family recently, she was shocked to see her sister in the prom dress.

"When I walk through the front door to my parents' house, Annie is wearing my prom dress and my grandma and mom are taking measurements. I asked them what they [were] doing and they said that I'm being an a--hole for not letting Annie use it," she shared.

The woman screamed at her sister to take the dress off, but her sister explained their mom lied and told her she had changed her mind.

"I yelled at my mom and grandma because they tried to go behind my back and even change the dress to better fit Annie ... I cried and yelled at them. As soon as Annie came back with my dress, I took it and packed it down ... I don't feel like I was in the wrong for not letting her use it, after all it was all my dress that I paid for and I even offered to pay for her dress," she concluded.

READ MORE: High School Slammed After Requesting ‘Front and Back’ Photos of Girls’ Prom Dresses

In the comments, Reddit users backed the woman, with many slamming her family for going behind her back.

"If they are cutting up the dress to fit Annie's frame, then you're not 'letting her use it,' you are GIVING her the dress. I don't see how they can make the dress fit you again after. No is a no," one person wrote.

"Classic case of 'meddling mom.' There was no issue concerning the dress until your mom stuck her nose in and created the problem. Your family needs to respect your belongings and your wishes and boundaries that go along with them," another commented.

"They are literally cutting up YOUR dress that you paid for yourself. That’s not letting your sister borrow it, that is making it for her and giving it to her. Your mother had no right to let her have your property. Honestly, if I were you I’d demand that my mother pays me back for the sum of the dress because what they are doing to it is irreversible," someone else chimed in.

Britney Spears Loves to Wear a Mini Dress

Below, check out photos of Britney Spears wearing a mini dress over the years.