My registration runs out on March 6. I'm moving to a new city same state Feb 15
Do I use my present address... does it take a long time for them to return the
Stickers?

Do they not have a tag office where you are moving? Every county in GA and most cities have tag offices.

You are allowed time after you move. Start the process about 1/25 and use the new address.

I'm afraid I don't know what a tag office is... so perhaps we don't have one
In New York

That's this week... I'll do that so if I got stopped for any reason, I'll still be
Within the period covered. Thank you (again)!

Tag office = DMV.