It's unfortunate that (at least in my experience) Apple makes you wait 3 days to enable two-factor auth. I'm still waiting and crossing my fingers that this gets patched ASAP.
They only make you wait 3 days if you've modified any of your information recently. From what I've seen they've also taken down the site that contained the security flaw.
It already got patched. Or rather, Apple disabled password reset functionality already. In fact, the article was already updated an hour ago to say that.
I just activated it on two accounts (including one account that didn't have an Apple device attached, so I had to use an SMS device) and it worked right away.
