At some point you must take control of your life, sure the visits won’t be frequent but how often does she see/did she see her children whom are adults? (Aka the thing you’re about to become). Also, the experience will be liberating, life-changing, and overall beneficial if you can afford it! You’re about to become an adult and the biggest part of that is making YOUR decisions, not following the guidelines of others unless you specifically want to. I have felt this same pressure with my family and upon my explanation have convinced them to side with my reasoning. I understand this probably isn’t going to work for you and you may have tried it, but you can’t let your grandma cripple you now, it’ll make a lasting impression that you’ll later regret.