Chances for UCSB/UCSD?

UW GPA: 3.6/4.0

WEIGHTED GPA: 3.9/5.0

APs: AP Government, AP Psychology, AP Statistics, AP Biology

ACT: 30 (34 E 24 M 32 R 28 S)

12th grade course load: Human Anatomy, AP Statistics, College Credit English, Genocide, AP Government, College Credit Biomedical Innovations

Extracurricular: Varsity Football (first female on an all-male team), Varsity Soccer all four years, Varsity Field Hockey Captain, President of Health Occupations Students of America, National Honor Society, Renaissance, Rho Kappa

Volunteer: Special Needs Soccer Association, Pattonville Sports Camp, Ranken Jordan Childrens Hospital

Intended Major: Currently undecided

Freshman admits with UC GPA if 3.80-4.19
UCB: 12%
UCLA: 14%
UCSD: 39%
UCSB: 49%
UCD: 52%
UCI: 57%
UCSC: 83%
UCR: 90%
UCM: 92%

If you are leaning towards a major such as STEM, you should apply directly since these competitive majors are very difficult to switch into later. Take a look at UCSD’s capped majors.

https://students.ucsd.edu/academics/advising/majors-minors/capped-majors.html

Your GPA is below the averages for UCSB and UCSD. ACT is within range.
Write some good essays and these schools are possible.
UCSB: High Match
UCSD; Low Reach

Make sure you have some solid Match and Safety schools on your list. I would add UCI/ UCSC and/or UCR along with a few Cal States.
Good Luck.