Minimum age limit is 25 years.

Wht is such aneed to keep it so long..?

In fact the age for all spiritual activities/teachings should be 60 or beyond 60 years, when one gets free from all other worldly liabilities with full satisfaction and devotion.

Else it can be any age if one does not have any dreams to study as also does not want to marry and decides not to get involved in family life.

One can imagine the fate of a person keeping his legs on two boats, going in different directions or even in same direction.