my ipod 3rd gen is 8 GB ipod so its says its a 2 gen can i change that

Sorry, there is no such thing as a 3rd Generation 8GB iPod Touch.

What some people don't know is that when Apple released Model MC086LL it was sold as a 8GB 3rd generation unit by some retailers but It really had the same guts as the 2nd generation model MB528LL with upgraded software. ALL so called "8GB 3rd generation" iPod Touch serial numbers pull up in the apple support system as a 2nd generation unit. Because of hardware limitations, 2nd generation units are not able to upgrade to ios5, therefore your last update will is version 4.21.

cant do that. sorry

here is a page i found it says origanly they did make thim

http://everymac.com/systems/apple/ipod/specs/ipod-touch-3g-specs.html

That is not from Apple.

Apple never said there was a 3rd gen 8gb model.

Identifying iPod models

That page is wrong in its designation of the 8GB iPod touch as "3rd generation". As has been said already, Apple never made an 8GB iPod touch with 3rd-generation hardware, regardless of the misstatements by some dealers and web sites.

Regards.