I think maybe you are just freaking out … and will get a 3 or maybe a 4.
If possible try to get your parents to understand that they are pushing to learn material that is 3 or 4 years ahead of typical students. Very smart math students take a real AP Calc AB class in junior year, after pre-calc and other prep classes and still don’t get a 5.
Really good in math - yes - but shooting too high too early - yes.
I think maybe you are ready to take Calc AB in high school this next year, which would still really impress colleges, and get a 4 or 5 and an A. Would your parents go for that ? That would still qualify for really good at math. Maybe really, really good.
I don’t think even MIT would think poorly of a 1 from a freshman who has self-studied …