Regarding requirements and recommendations in the Vedic system of selecting partners for marriage, there is a Vedic system, but that cannot be done here. It should be made under the guidance of the guardians and the selection should be made on the basis of astrological equilibrium. So it is not possible to introduce such system in the present age. The only selection is that both the boy and the girl should be Krsna conscious, and the boy may be older than the girl at least by 2 to 5 years.
Letter to Gurudasa, 16 May, 1970