I recently got accepted into UCSD as a structural engineer. The classes in taking now are AP Lang, AP Gov, AP Physics, and AP Calc, along with Piano and Avid as my extra A-G Courses. I don’t know about you or how well you do in school, but doing well in challenging classes seem to worked for me. I’m not saying if you don’t take these classes you won’t get accepted, but I applied as an engineer which is very competitive.
Also just a side note, in their application UCSD has room for you to tell your story. They look for leaders. If you’re in any volunteer work, or extracurriculars like club or sports, try to take a leadership position in those and be involved so you have more to write about and more reason for them to select you.