Ask whether your CO2 laser treatment is a traditional ablative laser or a fractional one before you ask how many sessions you need. The two are described differently.
What Penn Medicine says
Penn Medicine writes: With ablative laser resurfacing, most people only need one treatment with a traditional (non-fractional) ablative laser. It adds: Non-ablative or fractional laser treatments have shorter recovery times, but you may need multiple sessions.
Reading that in plain words
A traditional ablative laser points to one treatment for most people. A fractional laser points to a shorter recovery and the possibility of more than one session. Neither sentence gives you a number for your own skin, so the count is a question for your provider after they have examined you.
Confirming the laser type and session count
Get the laser type in writing from your St. Augustine provider, then ask what session count they expect for it. If you like to see how laser methods are compared on paper, there are two papers on laser hair removal, not resurfacing: a PMC paper on a rotational approach to medical laser hair removal and a PMC study comparing traditional and in-motion Nd:YAG laser hair removal.