UC’s only accept in-coming Freshman for Fall along with most of the CSU’s, so Winter applications are not possible. UC’s do take in account your EC’s so having 4 years devoted to some of your EC’s vs. 3 years may be deterimental. If you meet all the UC/CSU a-g requirments prior to Senior, there is is no reason not to apply. You do not have a defiinite SAT score yet and you may want to give yourself time over the summer to work any problem areas if you do not achieve your goal, so that may be another reason to continue with Senior year. Since you claim your application is not stellar, this gives you more time to polish up that application. Do what you think is best for you, but I would reconsider staying for your Senior year.