"Proposing" vs. "Declaring" a Major

“Proposing” a major is simply indicating an interest in a major. “Declaring” a major is a more formal process that you go through with your department or major advisor. If you listed a major on your UC application, it initially shows as a “proposed” major in the MyUCSC portal (you may have updated this since filing your admission application). Students who are already attending UCSC, or new students who have already filed their Statement of Intent to Register for the upcoming term, can request an update to their proposed major online. Note that there are some restrictions on proposing some majors. Students who enter UCSC as frosh are expected to confirm their proposed major by the end of their first year, and be formally declared in a major by the deadline in the spring quarter of second year (or equivalent). Students who enter UCSC as junior transfers are required to be declared by the deadline in their second term of enrollment.

You do not need to wait until your second year (or second term, for transfer students) to declare. You can (and should!) petition to declare your major when you have satisfied major qualification requirements or reached your deadline, whichever comes first. 

Researching a major's requirements early is important, so that you can be sure to take the necessary classes to both meet the major's qualification requirements and to confirm your interest in and ability to succeed in the major.