Of course you should
if you think you need to. There was an article in Latitude 38 this month about a race here with a lot of So. Cal's in it. They complained the race had been postponed and eventually canceled because the winds were only 5-8. Someone from So. Cal. said that was standard racing wind down there. We are used to sailing in 15 to 20 true or more, with 130 jibs and full mains, but racers reef, too. Plus, as everybody else will tell you, if you need to reef and do the boat sails faster than on its ear. If you know your C25 you'll know that you should reef the main first especially for racing.