I've learned to ssh for the first time, and am logged into my university mainframe account. Can I change my username without root? Or is it like a password where I need root?
Your username is determined by the system administrator when the account is created. You pretty much need
root level privileges to change it.
Your password is not fixed and can be changed with the
passwd command. You need to know the old password to change it, and the system may have restrictions (e.g. can not change more than once a day).
Yes, you need root access to change your username if the system uses passwd files for authentication. However, most likely the access at your site is controlled by means of
YP or other centralized account management services
You need not
root access to change your password as soon as you know your password and
passwd utility is available to you.