Since you are still a Junior, doing well academically will definitely help with your UC GPA. That said, the UC’s tend to be unpredictable and each campus will individually determine the weight of the 13 areas of criteria they use to admit applicants. Essays alone will not overcome less than stellar grades but the UC’s offer these prompts in the PIQ’s where you could explain your grade issues. Just remember, do not emphasize any excuses but use it to show how it has shaped you as an individual and what you have learned from it.
4. Describe how you have taken advantage of a significant educational opportunity or worked to overcome an educational barrier you have faced.
5. Describe the most significant challenge you have faced and the steps you have taken to overcome this challenge. How has this challenge affected your academic achievement?
All you can do is your best, do not fixate on any particular school(s) but find schools that are best for you based on your academic stats and abilities. As a California resident, you have access to 9 UC schools, 23 Cal states and numerous Private Universities where you can receive a wonderful education.
There is nothing wrong in applying as Undecided for many schools that allow you flexibility, but realize especially for the UC’s, switching into competitive majors later may not be an option.
There are plenty of colleges that would love to have you has a student and best of luck.