I know this is true when you are a high school student, but what if you are already in the college you chose, or even transferring and wanting to join?
Depends on the college. Research your college’s honors college/program policy.
At my school (Penn State), the requirements for getting in later through a gateway program are usually more stringent, like having a 3.7 cumulative college GPA. That’s tough, especially in harder majors. Like elliebham said, look up your honors college’s website and see what they have to say about it.
Entry into my school’s Honors College is open to current students but it’s more rigid and they are less likely to admit students past like, second semester of Freshman year, because there are quite a few graduation requirements within the HC that are time consuming and can’t be made up after a certain point.
In my school, you can apply to join the honors college, but the requirements are more stringent.
In fact, I was one such student who applied to join the honors college in the beginning of my second year. The requirement was a cumulative 3.6-3.7 GPA, among other requirements.
It can be a bit difficult, and policies will differ from school to school, so you should check with any specific school you want.