She has 10 T-shirts and singlets of different colours to select from each day, all with "I am Madeline" in bold print, and her friend Emily Evers is also on board with the challenge.
The challenge is also about raising money.
Initially Maddie raised money for World Vision's 40-hour famine, but has now set in her sights on a $5000 fundraising goal to help build an orphanage in Nepal.
Maddie is supporting an organisation called Every Village, which is trying to raise $60,000 to build an orphanage for a minister, his wife and 21 orphans by the end of the year.