To be fair, the city limits in Austin are pretty huge, already encompassing lots of what would qualify as the suburbs. Take, for example, the West Gate/South Manchaca/Stassney/William Cannon area (marked as Emerald Forest above), where there's already heavy build out going on.
Don't want to give you a false sense of optimism on this, but an article I recall reading last year speculated that Fiber penetration in Chicago could begin outside the city and work its way downtown, rather than the other way around.
I am in Austin city limits but outside the city center and we are nowhere close to getting Google fiber. I wouldn't get too excited by this, yet, especially if you're not in a densely populated part of town.
They provide maps of the rollout too: https://fiber.google.com/cities/austin/fiberhoods/