If your only or main email account is the one associated with your current Internet provider, you must let your contacts know that your email address is changing to your Gmail address. If you want to keep your personal email private, you can always create another Gmail account to use for your personal email and only use the Gmail account associated with GFiber for GFiber-related communications.
Before you discontinue your previous Internet coverage in preparation for your GFiber installation, be sure to email all of your contacts your new Gmail address and ask that they use that address from now on.
The Gmail Help Center provides up-to-date information about how to transfer your email address and contacts from other email providers to Gmail.