मनुस्मृति - वृद्ध युवा

न तेन वृद्धो भवति येनास्य पलितं शिरः ।
यो वै युवाप्यधीयानस्तं देवाः स्थविरं विदुः ॥

- मनुस्मृति

He is not considered old (and wise) just because he has gray hair. One must be well educated to be considered so. The Gods consider even a young man as matured if he is well read and educated.

- Manu Smriti