IPhone 3GS keeps restoring when update i try update to iOS6?

It's my first time ever trying to update my iphone 3GS and when I tried to update it it kept telling me to restore my phone?

IOS6 will work on your 3GS.

1st i would back all your contact up them reset the iPhone to factory setting "erase all content and setting" which is setting / general / reset. This will clear all setting, apps, music and contacts

and start a fresh install of the ios6

Well then restore the phone!