First, it is actually advantageous to learn to be a fitness instructor after graduating from high school. For example, in terms of physical fitness, since most senior high school students are 17 and 18 years old, they are not only at the right age, but also in the energetic stage of their lives, so training is very easy for them.
Second, after graduating from high school, many people have good study habits and learning ability, can quickly understand and master the theoretical knowledge of fitness, can quickly combine theory with practice under the guidance of teachers, and can achieve twice the result with half the effort in learning.
I hope my answer can help you.