Mama has two cancers so I want to stop going to school and stay home to help. Ok at 19?

Difficult to answer. Your mother is very important, but so is school. You should try to help out with your mother as best you can, but get assistance from other family, friends, and community resources. Your motive is noble, but you should not jeopardize your future by quitting school. Speak with your mother's social worker that should be working with her oncology team.
Your decision. Whether or not to become the care giver for someone with cancer or take time to be with a family member with cancer is a personal decision. There is no medical answer to this question. This is a question of the heart and a family matter.