to name a few, there is johnny depp, daniel radcliffe, jim carrey, ben foster, and nicolas cage. how are they even quilify anyway.
You don't need a high school diploma (or college diploma) to do a lot of things. Outside of medical, legal and a few other fields.
You can actually pick up some books, teach yourself and more importantly do great things without every going to college.
Most of our greatest entrepreneurs, actors and people in public life dropped out of college (and yes, some out of high school).
You should finish high school though.
You don't need to know how to do math or science to be an actor. Acting is an art. If you're a great actor then it doesn't matter if you have a diploma. Some stars become actors when they're really young and they don't have time for school. They don't need it either because they already have a good paying job as an actor.
You don't need qualifications all you need is a good audition and you get cast