If i want to be a novelist, but also a teacher what should i do i college.?

To teach high school cles, major in the field you want to teach - English, biology, physics, etc - and get education certification. To teach below the high school level, they often expect an education major instead, and some states require a masters degree, so look up the requirements for your specific state. You don't need any college degree to be a writer, but you can always take cles in it.