Accepted off the waitlist as undecided

I just got accepted off of the waitlist into my top college but as an undeclared major. How hard is it to declare a major at UCSD? I’d want to do neuro or psych. Thanks!

Psychology: super easy. Click a couple of buttons and you’re in.
Physiology and Neuroscience: harder; because it’s in the Division of Biological Sciences, this major will be capped next year. You’ll have to apply to get in and no one knows how many students they’re accepting yet. I’m sure it’s not impossible, but you may want to look deeper into psychology or cognitive science.

I got into my first choice major from undeclared, hbu?