advise to my japan rail pass

hi!!! my name is florentina, i'm argentinian

I will be arriving to Tokyo (Narita Airport) on 12nd April. I will be in akihabara.

My itinerary is as follows:

12 to 16 April TOKYO
17 April Tokyo to KYOTO, till 19 april
20 april Kyoto to TOKYO
21 april flight to OKINAWA (from Narita) till 24 april
24 april, I plan to stay close to Narita airport
25 april flight to home!!

I read that in okinawa the JR pass is not used.
Then, I don't know if I should get a pass for 7 days, which could enable 15 to 21 April, or maybe I would spend less money if I buy the passes individually, each way.

Thank you.

Yours sincerely,
florentina