Super Tiny Aster novae-angliae 'Purple Dome'

I ordered two of the Aster novae-angliae 'Purple Dome' aka Purple Dome New England Aster because I love the deep purple color of the flowers and I wanted something that would bloom in late summer or early fall, like a hardy mum, but something that would fit into a smaller space. These looked like a good dome shape at 24 inches tall and 18 inches wide.

I saw online that they ship in 5 inch pots, so I was sort of hoping for something a little larger to arrive. I was surprised that these little sprouts were only about 2 inches wide. They have a long way to go, and can hopefully bloom this fall. My lavender arrived 3x as big in a pot half the size, what gives?

Aster novae-angliae 'Purple Dome' arrived smaller than I was expecting, I hope it grows quick and can bloom into a nice dome this fall.