Why is it wrong to say that Princess Zhu Huan is called "Princess"?

In ancient times, Gege meant the daughter of an emperor or monarch, but the name Zhu Huan Gege refers to the swallow played by Zhao Wei. She is not the daughter of a real emperor.

This will start with the plot of this TV series. Wei Zi, played by Ruby Lin, is the real daughter of the emperor, but Wei Zi met a kind street performer-born swallow on the way to find her father. Wei Zi wanted to entrust the swallow to the palace and give him a token to prove her identity. However, due to mistakes, the swallow was mistaken for her own daughter by the emperor and was named Princess Zhu Huan. It can be seen that the swallow referred to by Princess Zhu Huan is not a real princess, so it is wrong to call it a princess.

Later, the swallow took Wei Zi to the palace, first as a maid-in-waiting, then contacted the emperor, and gradually told the emperor what happened. First, the emperor flew into a rage, and the swallow and Wei Zi escaped. Later, the emperor finally forgave them for cheating the king, and named Wei Zi Pearl Gege, and Wei Zi was the real Gege.