http://www.straitstimes.com/lifestyle/8-signs-ive-hit-middle-age
Most of the characteristics featuring old age are prolonged in proportional to life span. But, appropriate age for pregnancy hasn't been prolonged. Despite this fact, average age to marry is becoming older and older.
So, most of my friends think that we should marry over 30 years old.
It will shrink the period of ability to be pregnant.