This screams rich parents got blessed with a horse girl daughter but neither parent has any experience in riding or horse care in general. My bet is: Gracie cried “Daddy, I want a pony!“ and Daddy went and got her the youngest pony he could find, not knowing she can‘t ride it for years to come. Now they don‘t want to pay for a second horse so they come up with whatever this tomfoolery is so their “established“ equestrian daughter can learn from a schoolmaster until her Arabian is of age. Established my ass. Took me 15 years just to somewhat become an acceptable rider.