If you've only ever logged into your account with your CSUSB credentials and you're planning to leave CSUSB, you'll need to ensure that your OSF account is accessible through an alternative email and password.
Connect your OSF account with an additional email address
Go to your user settings and select the 'Account Settings' tab. You will have the option to add an 'alternate email'.
You will need to confirm this email address twice, first by clicking on the confirmation link that is emailed to you and, second, by logging back into OSF with your CSUSB and accepting the addition of the new alternate email.
Set a new password
With your alternate email confirmed, log out of your OSF account. When you attempt to log back in, select the option for 'Reset Password'.
Once complete, you will be able to log in either with your CSUSB or you alternate email and password. When you have left CSUSB, you can delete your CSUSB email from your account.