At launch, the subscription you have bought will actually start counting down. You get to keep whatever you've gotten from that subscription (credits, teleportation tokens, votes) so far; they all roll over, month to month.
In some ways, your subscription hasn't even started!
But yes. The 12 month count down does not begin until the game launches.
One thing that just occurred to me is some of the timing...
Say you start your subscription on the the tenth of the month. Right now, you get your allowances of credits and tokens on the tenth of each month.
But say the game launches on the twenty-fifth. Does your subscription start from then? From the previous tenth? The next tenth?