If there is spring at that age, things should be different. What does this sentence mean?

From the sacrifice of Tang Dynasty poet Zhang Ji.

The word Wenchang, Han nationality, Wujiang (now Hexian County, Anhui Province), looks at Suzhou Wu (now Suzhou, Jiangsu Province). His ancestors moved to Hezhou, and later he was from Wujiang (now Wujiang Town, Hexian County, Anhui Province). The world calls it "Zhang Shuibu" and "Zhang". Zhang Ji's Yuefu Poems are as famous as Wang Jian's Yuefu Poems, also known as "Zhang Wang Yuefu". Famous poems include Song of Xia Sai, Complaining for Women, Song of Picking Lotus and Song of Jiangnan.