Augh overbearing parents really are the worst. The only reason mine are leaving me alone now is because they feel guilty about my depressive episode and how they didn't prepare me enough to handle life and so I told them they need to back off so I can get on my feet myself. And I've learned often that sometimes the best way is just to bait them with issues that aren't as important so they'll back off on the ones that are as well as pushing for a lot and then accepting a little (like, I want this and this and this, okay fine just give me this one) and eventually over time get all the things you want. Especially with parents who want to keep you as a baby your entire life you kind of have to force distance. Kind of gradually but force it all the same. Which is where understanding your mom and how she acts along how to best bring up topics to make her understand while keeping a lid on all her counterarguments come in handy. It's really tough but eventually do-able.

Best of luck!