Question About Upgrade - Still in Contract

Hello All,

I currently have the iPhone 4s from AT&T with a contract that will expire in 3 weeks and plan on switching carriers to Verizon. I plan on getting the iPhone 5s (gold ) but am concerned I may not be able to get one if I wait 3 weeks as current orders are expected to ship in October.

Is it a good idea to order an iPhone online now (get it early) and then activate it after my contract with AT&T is up?

Thanks!