On Princesses and Favorite Colours

Sylvia 'I am going to be a princess for Halloween! A pink princess!'



Sylvia, a few weeks ago, very consistently 'Pink and purple are my favorite colours!'

Sylvia, now, since about a week 'Pink is my favorite colour!
Me 'What about purple?'
Sylvia 'No!'
Me 'It used to be your favorite colour, right?'
Sylvia 'Yes, but it is not anymore.'