Howdy, congrats on getting the batch going.
Fermentation speed is dependent on many factors, but a big one is temperature. So, just by cooling it off some, you're going to slow it down and that's fine.
Ideally, you actually rather have the beer fermenting around 68, but good luck getting that with a/c. One quick trick to try is put the bucket/carboy in a shallow water bath, place a tshirt over the fermenter and drapped into the water. Now point your fan at it. The fan will blow cause the water to evaporate from the shirt, cooling the whole thing down further and the water from the pain, will wick up the shirt.