Share my account info doesn't appear in Account menu
I am having the same problem. I believe I pressed "not now" (back button) instead of agreeing immediately to the terms of service.  According to an 'idigitaltimes' article* from two days ago:  

"If you want a little time to think over your decision, you have until September 25 to accept the terms. You can press “Not Now” which essentially means you haven’t agreed to the new terms. As the expiration for the new terms agreement draws near, WhatsApp will remind you again to agree to the terms. You can then choose to leave the green Facebook sharing check marked to share or uncheck it to opt out of sharing."

We want to address this issue right now... But it looks like we will have to wait until Whatsapp 'offers' the new terms of service again.  It's fishy.  

*ARTICLE:
http://www.idigitaltimes.com/whatsapp-facebook-opt-out-how-stop-ad-related-data-sharing-between-your-accounts-552594