I've been keeping expectations low by getting bad grades.
That doesn't make a lot of sense. why would you do that sort of thing?
I don't want to feel pressure from my parents.
If you are trying to get bad grades then you are smart enough to get good grades. You shouldn't have set of to try and fail on purpose. You should think about trying to have more self-confidence.
What does thinking about my self-confidence have to do with my bad grades? I don't see the connection.
Because you are worried about pressure you are showing you lack confidence in thinking you can get good grades.  You should know that you are smart and feel good about trying to do better.