i need the older itunes versoin

I believe that Windows XP is only 32 bit. At any rate, Apple still offers a version of iTunes that will run on Windows XP. Find it at https://support.apple.com/kb/dl1614?locale=en_US.

That is great, but I have another question for you. The iPhone 3GS cannot communicate using 4G or LTE. Many networks are decommissioning their 3G and 2.5G networks to make way for their 5G network build-outs. Do you live in a country and subscribe to a carrier where 5G is still off in the future? If not, you may not get much service life out of your new phone.

You will need to talk to VZW for these answers. Tell them that you plan to use an Apple 3GS in Kalispell and you want to know how long you can expect to use it before they decommission their 2.5G towers. You should also ask them if voice-over-WiFi calling is possible on the 3GS. Good luck.