'We've been struggling for a year, and I'm not pulling in as much as I'd hoped. I've considered taking a second job, but honestly, I'm not sure there are enough hours in the day.' She laughed without any trace of humor. 'Dorothea's wages are modest, but it's extra money we don't have. The only thing I can think of is moving into a smaller house. Or an apartment.'
'But this is our house.' All my memories were here. The memory of my dad was here. I couldn't believe she didn't feel the same way. I would do whatever it took to stay. (14.14-15)
Nora's mom reveals the sad state of their financial affairs and tells Nora they may have to sell the house. Part of coming of age means learning about all the things that worry adults, such as money and mortgages and the cost of keeping up a house. Nora is smacked in the face with all that here.
There is some immaturity in Nora's response when she suggests her mom doesn't feel sad about the idea of leaving the house. Her mom doesn't say as much, but it's easy to imagine she doesn't want to sell her home. However, she knows that she has to take care of finances. Nora still has some growing up to do, but she gets a taste of the cold, hard reality of adult life in this passage.