Sounds like you have completed your freshman year of college. If you want to transfer to a college such as UPenn, you will need to wait for the application for Fall of 2024. In other word, next March, in 2024.
So you will essentially need to take a gap year, or stay at UCLA and get very high grades and great professor recs in sophomore year. You could try community college for this coming year too, but it might not be great for your application to have 1 year at UCLA and 1 year at community college, unless it was a cost issue.
Why Penn? What about the financial aid aspects? Can you afford it? Do you have reason to believe it will be more affordable?