To take care of someone that wasn't her responsibility sounded like kindness to Mable, but maybe there was a distinction that only adults were privy to.  Whatever - the difference didn't matter to Mable, so long as she got to make pretty flower designs in the cloth.

A new dress would have been nice, of course, but...  "Yes, I'm sure.  I like this dress a lot, and I'd feel bad to replace it so soon."

She followed Nettie to the counter to purchase the cloths, eyes still wandering around the store at all the pretty things she would be sure to afford one day.  At the counter, a display of brightly colored thread quickly stole Mable's attention, and she took a pink colored bundle before she could think much of it.  "Woah, Miss Nettie, can I please get this color?  It's my favorite!  I don't need any others but this one!"