I purchased my first Glock a couple months ago and I'm still new to the sport and obsession of owning guns

Anyways, is there any rhyme or reason as to which Glock model gets its number? I understand the original 17 round Glock 17. Makes sense. But why is the smaller 19, a higher number? And why is the even smaller 26, called a 26? These may be dumb ass questions, but as I'm trying to learn about Glocks and which model is which, it would be helpful to have some understanding of the method to the madness.