Would it be smart for me to accept my admission at a college even though I'm waitlisted at my top choice?

You have to put down a deposit at a college by May 1, but if you get accepted off the waitlist for UCSD, you can put down your enrolment deposit there after May 1 but you will lose the original deposit you put down at UCD.

I also got waitlisted at my top college- here is my perspective. The deadline to accept and pay a deposit for a college is May 3rd (typically May 1st but pushed back this year). Colleges often do not know how many people they will admit off the waitlist until after May 3rd when they know for sure how many people already accepted there offer. That's why it can take until late June and early July to hear back if you have been offered a spot of the waitlist or not. It is to your advantage to take the offer at UCD before May 1st because you will not hear back from the other college until late into the summer, and in late summer you will lose your opportunity to accept UCD. It is also possible that you will unfortunately not get offered a spot at UCSD and by the time you hear that, it will be too late to commit and accept an offer from UCD.

TLDR - I would advise you to accept the offer at UCD