Yes, I do agree with Mathilde. She is young and she can perfectly change three times. The fact that The Queen and The Princess wore black and white in the morning could be a choice from both ladies, due to the fact that the day would be celebrated in a less festive and colourful way due to the economic crisis.
On the eve of the National Day, she chose a grey cocktail dress with bare shoulders and she wore the same earrings as she did when Queen Elizabeth II came to visit two years ago. This dress was not new.
For the Te Deum Mass, she choose another outfit which had already been worn, most notably for the christening of the baby of the Princess Mary of Denmark of which Mathilde is godmother.
In the afternoon, a new outfit in bright pink and white was worn. The fascinator on the head was in the same style as she wore three years ago for the arrival ceremony in Antwerp of Queen Beatrix, Prince Willem-Alexander and Princess Maxima. This time, the bows were smaller and as well in pink instead of red three years ago. This hat for the Parade was a Fabienne Delvigne creation at the time, so I guess that she made this one as well because it is the same design.
In the evening, the Princess choose white and green. Another older outfit, which has been worn several times before.