History of Dharmashastra (Ancient and Mediaeval Religious and Civil Law in India) v2.c24.s1.328

v2.c24.s1.328

⁸⁵¹ As upanayana was usually performed in the 8th year from conception or birth, the period of studenthood (if it was to be 48 years) would not end till a man became 56. Only a householder could consecrate the śrauta fires. So if the man was to marry after fifty-six his hair would be turning grey and by following the smṛti rule he would run counter to the Vedic injunction. Thus smṛtis would be opposed to śruti and Jaimini's conclusion in I. 3. 3 is that when that is the case smṛti is to be disregarded.