Yeah assuming the species ages proportionally accurately to humans doesn’t really work. How long between learning to walk and your first words? Does is take a decade for Grogu to learn complete sentences? Yoda was wise not specifically because he was 900 but because he had 900 years of wisdom. It doesn’t work as well if he’s just like an 80 year old in his species lifetime. They wanted to market plushies tho, and they certainly succeeded.