Miss maudie's not very upset about the fire. what's the reason she gives about why she always wanted a smaller house?

When Jem gives Miss Maudie his sympathies for the loss of her house, she says, "Always wanted a smaller house, Jem Finch. Gives me more yard. Just think, I’ll have more room for my azaleas now!"
She tells Jem and Scout that she'll be able to have a bigger yard which means more room for the plants she loves to tend. She also calls her old house a cow barn and says that she had thought of burning it does herself. 

Miss Maudie's reaction to her house being burnt down furthers her likable character. Her character is one of the mother figures for Scout and Jem since their mother is gone. Throughout the book, she is able to look on the bright side of things and is more accepting of others than most of Maycomb.