Medically, the best age period to have babies for a woman is

25-28yr. However, a woman with healthy productive system could have babies at any time before menopause. However, after 35, the risk of having a congenitally deformed baby is much higher than before 35. With a condition that the hu*****and's sperms are good, the woman who gets pregnant after 35, is suggested to have an aminotic puncture at w20-25.
aminotic puncture is a prenatal examination to exclude congenitally deformed babies, specfically for pregnant women who is older than 35yr.