OP, you asked if it was necessary to take a CS class in HS. Harvey Mudd College, Claremont,CA several years ago instituted an intro CS class for those with little programming experience in order to try to attract and retain more women into the CS major. They observed that those with lots of programming experience before college (mostly males) tended to monopolize the discussion during intro classes, and intimidate those with less experience. Mudd has found that this and a few other steps have helped them to be very successful in bringing more women into their CS major.