My sister lives with my father and stepmom in Florida and is going to turn 18 in the beginning of September. Although she is still attending high school, they told her she needed to be out of the house by 12:01am on her birthday. Are they legally capable of doing so just because she will be "of age"?

my sister lives with my father and stepmom in florida and is going to turn 18 in the beginning of september. Although she is still attending highschool, they told her she needed to be out of the house by 12:01am on her birthday. are they legally capable of doing so just because she will be "of age"?
Yes they are able to this because she is grown and old enough to do it... but if they kick her out on the streets its most likely not legal