I want to tell my girlfriend that I don't want to marry her because it's not necessary. Did you hear that?
Why don't you want to marry her?
I am tired of her meddling
If you have problems in the relationship, the first thing you should do is talk about them together. However, if the problems are insurmountable, then you should end the relationship so you can both find someone who makes you happy.
That's stupid, why should I be the one to change? I should be able to do what I want.
Ideally both people would be doing what they want in a relationship, and their partner would accept their behavior. If your partner's behavior bothers you, you should talk to them about it. She might be meddling because she cares or is concerned.