Most yards around Mt. Juliet and Hendersonville want their first cut somewhere in the second half of March, but the calendar is not the trigger. Growth is. Once the grass is actively growing and you can see the difference from one week to the next, it is time, and waiting past that point means the first cut removes far too much at once.
The rule that matters more than any other is the one-third rule: never remove more than a third of the blade in a single pass. Cutting a six-inch lawn down to three inches strips the plant of the leaf surface it uses to feed itself, and it responds by pushing shallow roots and thin growth exactly when it should be building depth for summer.
For the tall fescue that covers most Middle Tennessee lawns, three and a half to four inches is the working height, and higher through July and August. Tall fescue shades its own soil, and that shade is the cheapest crabgrass control available. Cut it at two inches in June and you are effectively planting weeds.
Bermuda runs the other direction. It wants to be cut lower, around one and a half to two inches, and it wants to be cut often. If you have bermuda and you are mowing it every other week at fescue height, it will thin and stem up under its own canopy.
The last piece is blade sharpness. A dull blade tears the tip instead of slicing it, and torn tips turn brown within a day. If your lawn looks hazy or grayish the afternoon after a cut, that is a blade problem, not a water problem.