Latest version of iTunes downloaded, won't work with my new iPhone 6S

I have a 64G iPhone 6S that I got today. The version is 9.3.2 . When trying to plug into iTunes to put music on my phone, a window pops up saying The iPhone “(redacted)” cannot be used because it requires a newer version of iTunes. Go to www.itunes.com to download the latest version of iTunes.

I have downloaded the newest version of iTunes (11.4). I restarted my computer. I restarted my phone. It still won't let my phone connect to iTunes.

I'm confused and very irritated and would like to know what might be going on and how to fix it.