Where/what department?
Any primary care shadowing or experience?
Every premed applicant likely has some tutoring, and 100 hours is barely "average." You were also a TA so you may be okay, but it seems low.
Most schools screen out applicants with fewer than 150 hours of service orientation activities: food distribution, shelter volunteer, job and tax preparation, transportation services, or housing rehabilitation. Looks like you have zero in this category.
Many UC schools like to recruit applicants who grew up near their campuses. Where did you grow up?
As it stands, you are a strong PhD applicant and should be in line for scholarships. Four first-authors... great work!