How do I convince my dad and teacher to let me switch to the regular math class?

[Mizz Cali]

I'm in an advanced math class and it's really hard for me, even when I try be absolute hardest I still may not get it. I want to switch to a regular math class so I can get better grades... But everytime I ask my dad he says no then says that class is for dumba.s.s.es and that I'm not stupid. But when I tell my aunt she understands and says it's not a class for dumb people it's just not as hard, the stuff I'm doing is really hard even for her too. I asked my teacher once and she said to just try harder but I really think I should just switch. How do I convince them to let me switch? Thanks