Simple, if you learn FIRST other styles (breast strokes蛙式, e.g.) which are easier to learn, you will not have high motivation to learn Free Style (自由式).
雖然叫做"自由式", 實則這泳式需要更大的身體協調 - not very free in a way.....
Yeah, I was quite grown up when I started to swim.
I have seen a lot of cases however that when they can swim in other styles, they have no motivation in other style. Surely a good coach should be able to make us swim in whatever "suitable" form.