What was special about Anne's arrival in Holland?

Anne's mother and Father moved to Holland in September of 1933. Her sister Margot joined them in December. Anne's arrival the following February was special because it was Margot's birthday, and Anne was her gift.

Because we're Jewish, my father immigrated to Holland in 1933, when he became the Managing Director of the Dutch Opekta Company, which manufactures products used in making jam. My mother, Edith Hollander Frank, went with him to Holland in September, while Margot and I were sent to Aachen to stay with our grandmother. Margot went to Holland in December, and I followed in February, when I was plunked down on the table as a birthday present for Margot.