The UCs don’t determine your status by how many units you have left for your degree, its by how many you have earned. If you are a typical undergrad then at the end of 2 years you have earned enough to be considered a junior. The rules are on the UC website http://admission.universityofcalifornia.edu/counselors/transfer/minimum-requirements/index.html and other UC websites.
If you apply for xfer with entry in Fall 2020 then a concern is whether you will be considered a senior or high-unit junior since you will have been enrolled in college for 3 years by the time you enter a UC. Many UCs do not accept these applicants or limit them. See page 34 of http://admission.universityofcalifornia.edu/counselors/files/quick-reference-2018.pdf If everything you have taken so far and will take next year is lower division, no problem. Otherwise upper-division units are added to the lower-division cap of 70 semester units to calculate your total.