AITAH for refusing to pay for food?

I know the title looks bad but I need to explain a lot lol. So me 17m (almost 18) and my mum 37f is in a bit of an ongoing argument(?) right now. We get gousto each week (I don’t really know how to explain it but you just get all the ingredients and recipe cards for the meals) and I struggle with finishing a lot of my meals (dinner to be exact), I think it’s important I also struggle with binge eating, to try and tackle this I’m making it a point to stop eating when I’m full anyways because of these wasted meals my mum wants to charge me £5 per meal that I “waste” meaning don’t fully finish (I have a part time job so realistically this is possible for me to pay) but I’m refusing to pay this because 1. I’m trying to save as much as I can for my future 2. I have my own other bills to pay (like a gym membership and my phone bill) 3. I buy myself food for lunch and protein needs to make it cheaper for my mum and 4. I don’t think it’s bad to stop eating when I’m full?? Ask for anymore information you want but overall AITAH?