Adding World Connect To Brand New Account

So my family just switched back to ATT after trying Google Fi for a month and a half. We were ATT customers under a different account number since it was Cingular back in the early 2000s.

Our account is now under my name as primary and just a couple days old. We were told by one representative that we had to wait 90 days and another said 30 days before we can add World Connect Value to one of our lines.  I had these answers almost two hours into the call and going through three people early today.

Which is the correct answer?