Taking 5 years to complete high school

Hi, I am homeschooled, and I was wondering if you know if there is any way I could take an extra year to finish coursework. Right now I am supposed to be a senior, but I want to take an extra year to take some ap's and some more electives. is it possible to state that I am repeating junior year this year and have my senior year be the 2018-2019 school year? would this look really bad for my college applications? my sat score is decent (1430). Also, what are the rules for completing coursework during a gap year?