def calc_age(birthdate):
now=datetime.datetime.now()
bdate=datetime.datetime.strptime(birthdate,"%Y-%m-%d")
age=now.year-bdate.year
if now.timetuple().tm_yday < bdate.timetuple().tm_yday:
age-=1
return age
>>> calc_age("2001-11-18")
15
>>> calc_age("2001-10-18")
16