BMI is a poor health metric for people who train
Body Mass Index — weight divided by height squared — was developed in the 19th century as a statistical tool for describing populations, not as a medical diagnostic for any one individual. The formula can't tell what your weight is made of: a kilogram of muscle and a kilogram of fat weigh the same but affect health and appearance completely differently.
That creates an obvious paradox for people who train: an athlete with low body fat but a lot of muscle mass often lands in the 'overweight' or even 'obese' BMI category simply because muscle tissue is denser than fat at the same body volume.
More informative metrics for someone who trains: body-fat percentage (measured directly or via circumference tracking), waist-to-height ratio, and simply tracking body composition over time. BMI stays useful as a population-level statistic, but as a personal benchmark for someone who trains regularly, it's often misleading.