7 Days JRPass?

Hello,

Here is my itinerary:

Sep 11th 3PM: Arrive at NRT, go to Tokyo
Sep 14th Tokyo -> Kyoto
Sep 16th Kyoto -> Osaka
Sep 17th Osaka -> Kobe (day trip)
Sep 18th Osaka -> Tokyo, then NRT (flight at 530PM)

If I get the 7 day JR Pass, and activate the pass on Sep 11th, the pass wouldn't work on the 18th correct, it would expire 3pm on the 17th correct? Or would it go all the way to the 18th 3pm?

I guess we could also not activate the pass until the 14th right? What's your suggestion. Thanks!