Switching major from neurobiology to aerospace UCSD

I was admitted to UCSD for fall 2018 with a major of neurobiology but I want to switch to aerospace engineering. I’ve been a straight A student all of high school I have the work ethics to attain satisfactory grades. Is stressing out about not being able to change my major worth it? How easy would it be to switch? Is it impossible or are my chances high as long as I do well with my courses?

Here is the info but no guarantees: http://mae.ucsd.edu/undergrad/ugadmissions