Putting walmart aside for now, tell us how old the battery is.
Vehicle mileage and year? 3.8L V6 engine?
IF they measured properly, the battery shows it is/was fully charged. 12.6V is usually the norm. If the charging system is working right, it will likely read around 13-14V when running.
When cranking the starter it will likely (temporarily) fall to about 8.5V to 9.5V. I know I'll be corrected if wrong.
The CCA (cold Cranking Amps) is somewhat low and during a cold temp period it may not be strong enough to turn the engine over.
So, during warm weather you should be ok, but come winter (depending on your location) you might want to replace the battery.
This is why I asked how old the battery is. Batteries are usually good for 5 years on average. Some less than others.
Always buy the highest CCA battery and keep BOTH ends of the battery cables/ connectors clean and on wrench tight.
It doesn't hurt to have an in-vehicle load test done at least once every 2 to 3 years to ensure the charging system works properly. (Sooner if problems arise)
Keeping battery booster cables handy all the time just makes good sense, but in reality, proper preventive maintenance is what keeps you off the shoulder of the road.