I am still trying to figure out how anyone manages to earn a living and complete 1, or more, thru hikes of the various long trails.
If you figure it out, let me know.
Whoa Grasshopper. You are 18. The GRE is a long way off. Worry about undergrad before you get your knickers in a twist over grad school.
Good luck! Just do it! You will have the rest of your life to worry about boring stuff like school and work.
Wayne