People recommend if they don’t get in to a UC that they wanted during their senior year in high school that it is good to go to a CC for 2 years then transfer to a UC. But if you’re a let’s say, Computer Science Major, do you miss out on some Computer Science classes that you would’ve taken during your first 2 years?
Do people in their first 2 years at a UC take Computer Science classes if they're a Computer Science
In California, many of the good community colleges will have all of the lower division courses for the most popular majors. There is a website called assist dot org that lists course equivalencies between all the community colleges and CSUs/UCs. You should absolutely check that out to make sure you are taking courses that are guaranteed to transfer and count for your major. To aid with transferring, it is always best to attend a community college that is on the same calendar as the UC to which you want to attend (that is, go to a CC on a quarter system if the UC you plan to transfer to is also on a quarter system… same for semester calendars).
I took all my lower div requirements for CS in my first two years at UCD (except for one stats class). Check assist.org and make sure you’re taking classes at your CC that fulfill the prereqs for the UCs you’re considering, and fulfill as many of them as possible. If you do that, you should be fine. Depending on your CC and how far you get you might need to take a few lower div classes before getting into upper div CS classes, but you shouldn’t be far behind.
Research your community college just like any other college. Check the requirements necessary to transfer to CS, check the TAG opportunities, check the number and quality of comp sci classes. I know several transfer CS students who are doing well, and several freshman year year students who had to look for months for a job.