Yes it matters! My son was sick his sophomore year, grades dropped, had some C’s. Rest of grades junior and senior year were very good. Wrote about all of it …got a supplemental app from UCLA, which means he was on the cusp of getting in…he didn’t get in to UCLA, but did get in to Davis and couldn’t be happier and Davis is the best fit for him. I do believe the UC’s really do a holistic evaluation of the application. Good luck, keep your grades up and write thoughtful and positive PQR’s and work part time. Maybe UCLA, maybe not. But… maybe one of the other UC’s. Good luck to you and enjoy the process. You will end up where you are suppose to end up.