I've been doing booty workouts (bodyweight squats, lunges, clamshells, fire hydrants and donkey kicks) at home for 7 months. I do 3 sets 30 reps each of squats, clamshells, fire hydrants and donkey kicks and 3 sets 20 reps of lunges. After doing workout i always measure my booty and every time it comes around 38.5 or near to 39 inches. But on rest days when i measure my booty it comes exactly 39 inches. I dont know what am I doing wrong.