Only you will know the consequences of asking not to have a study. Will it create unbearable situation at home? Will your aunt be angry? If you’re not sure could you test the water?
“Aunt I would rather not have a study at this time”
when asked why not? You can say
”I attend meetings and that is enough intake for me at this time” “I don’t feel like it” “I just don’t” - always be vague never be controversial by saying “it’s a cult” etc
Be respectful but perhaps politely remind her that Jesus said “let anyone that WANTS to come take life’s water free. Ask her if she is going to force you to have a study.
Tell her that if you have any freedom of choice on the matter you would rather not study at this time since you don’t feel like it.
All of this assumes it won’t create unbearable tension in the house.
If so then study with bob be a respectfully bored student.