Who decided the marriage of the ancient princess? Does the princess have the right to choose? How long does it take to prepare from engagement to marriage?

The princess's marriage is not up to her to decide. If she was not accused of getting married as a child, she could make a choice within a certain range, from princes to princes' families, and then to princes' families in neighboring countries. There are no special rules on time. The long one takes several years, the short one takes several days, and it usually takes about one year to prepare.