Q. Do you get any extra benefits for being a full time high school student and also taking college classes as well?
A. You probably don't, unless you have a significant tax liability(unusual for a HS student), but your parents might.
The ability of the parent of a high school student to claim the education credit is limited. If these courses are provided by an eligible college, this cost qualifies for the Lifetime Learning Credit (LLC). The school must have policy of granting college credit for that course, already taken, if the student ever enrolls there. In other words, it is a requirement that the course be a college credit course, even if the student isn't currently a college student. It’s not that the student is post-secondary, it’s that the course is post secondary. Books are not a qualifying expense, unless included in the course fee. You must have paid tuition to the college and not the high school in order to claim the expenses on your return.
https://www.taxact.com/support/22177/2023/education-credits-high-school-student-taking-college-class...
High school students are not usually eligible for the more generous American Opportunity Credit, unless they are officially enrolled as a degree candidate.