My GFR, by that calculation formula, is 101.173, even though I have Stage 2 Mild kidney disease.
If you do that calculation and get 101, that is the determining point for hyperfiltration at your age. If your eGFR is lower than that, you are not hyperfiltering. If your eGFR is above that, you have the beginning of kidney disease and will breakdown your kidney in a short while, with truly lower eGFR values to come with your newfound kidney disease.