AITA for wanting my mum to pay me back my school money that she spent on herself?

The scholarship I got for university wasn't enough to cover everything. My family decided to keep the money they were going to spend on my tuition, and my grandma gave me money to pay for the rest. It was enough to cover all of my tuition and other costs at the time. The money my family would've paid, if they hadn't decided to keep it, was in my bank account. I tried to be careful with the money my grandma gave me and keep the majority of it separate. <br><br>When I went home for breaks, I noticed that my parents had bought some new things. It was stuff they'd discussed that they would buy eventually, but they hadn't planned on buying so soon. When I saw the new things they got, it didn't feel right. I had asked them if they were okay with money, because sometimes our income is lower than usual. And that's when my mum told me that they used the money they were originally going to spend on my tuition, to pay for some of the things they got. <br><br>She made it sound like they were spending money that they would've spent anyway, but it felt like they were spending money they didn't have because they didn't have to pay for my tuition. I didn't bring it up with them at the time because I was only home for a week and didn't want to ruin the break by being petty. <br><br>After signing my lease to stay in my student flat for 2nd year, I had to pay £900 more in rent than I did as a fresher. My student loan didn't cover it. My mum took control of my student account and paid my rent, and then took the rest of my student loan money. She said she was doing it to make sure that I didn't waste my money on something unnecessarily. But she spent a good amount of my student loan money. And she's been dipping into the money I had saved for tuition, to pay for things that my family needed. <br><br>She's paying me an allowance every week, so that I have money to spend. But the amount she's paying me is not enough to cover my living costs, and I still have to pay for some of my tuition. I feel like she's just stealing from me and controlling me. I wanted to ask her about it and tell her to stop, but my sister said I should just let them steal if I want to live at home peacefully. She said that my parents don't see it as stealing, because they believe they are entitled to the money they were going to spend on me. <br><br>AITA for wanting my mum to pay me back the money that she has spent from my student loan and tuition money?