First of all, we must make sure that this famous person did say these words, because some of them were fabricated by China people. It is easy to influence the formation of children's ideas and their respect for their alma mater in the future. Secondly, we can consider the combination of Chinese and foreign. China's idea is to integrate the ancient and the modern. The ancients used easy-to-understand poems, such as Mohe, Climbing the Yellow Crane Tower, and Looking at Yue. Contemporary celebrities use some inspiring or positive quotations, such as those of scientists, model workers, astronauts, athletes, writers or famous artists. In short, children should be easy to understand and accept; Third, calligraphy depends on what children mainly learn, but also on what textbooks are used in your school. For ancient calligraphy, we can find some positive calligraphers' sentences, such as Yan Zhenqing, Wang Xizhi and Zeng Guofan. Now, you can consider using pen calligraphy works, such as those of Pang Zhonghua and Gu Zhongan.
Hand, I hope it helps you!