Setting up a new right out of the box never used before Apple Watch. Wrong Apple ID defaults on iphone I am pairing it with

The 4th Apple support person solved the issue - got to Settings -> Messages -> Send & Receive -> Start New Conversation From -> and then select the actual phone number associated with the phone. It pulled the "Apple ID" information from the lists of email addresses on this list, and one of them was @gmail.com. Even after I deleted that email account (prior to contacting support) it was persistent in using address it already had pulled. Once I switched to the number in this menu, it correctly pulled the email address actually associated with my Apple ID. Things went smoothly from their other than AT&T not enabling the Apple Watch as yet ("account needs manual review").

Thanks for your incorrect input. It is a brand new watch purchased from Costco. And after talking to 4 different Apple support people I got the the person who quickly solved the problem. Thanks for your quick but alas incorrect diagnosis.