If you are getting the best grades you can, it’s time to ignore the parents and focus on your life goals. This is much easier said than done, I know that from first-hand experience, but I don’t know what else to advise. If they have decided that you are stupid no matter what, I don’t know what to do about it. They seem like the type of people who refuse to consider the evidence. I’ve met up with too many hard-knuckled folk like that. It’s hard not to fight them but it never does any good. Energy is more wisely expended in getting on with one’s own life.