I'm thinking of cutting my grandparents out of my life and possibly my parents as well.
Why cut family out of your life?
I want to do things my own way and they don't like it
Don't do that. Cutting people out of your life will cause you to regret it later.
You don't understand. They are just so annoying.
It's normal to be annoyed by family members, especially as you're becoming an adult. But try not to cut them out entirely as long as they're not abusive; you're likely to want a relationship when you're a little older.