While you're in high school you can take college classes.
Credits can count for both high school and college.
Ask your high school counselor how this works. CAP Program Receive a guaranteed transfer to UC Berkeley by applying to UCB during November of your senior year. See your high school counselor for more information. High Schoolers Can Take Classes High School students in good standing may take one class per semester at Sacramento City College for no fee. Students must pay for books and parking.