Here is a list of English age terms for you to consider

 Here is a list of English age terms for you to consider

Newborn: a child up to a few months old.

Baby: 0-2 years old, especially younger.

Toddler: a young child who is learning to walk.

In the terrible two's: a young child who is two years old and demanding to have anything he or she wants.

Youngster: children, mainly up to age 10, but for an older person born in the 1930s, this would include anyone under age 25 or younger than they are.  

Child: any age under 18, but especially under teenage.

Kindergartener: a child in kindergarten, ages 3 to 6. The word comes from German: kinder = child; garten = garden, so a kindergarten is a garden of children.

Primary school age child: grades one to three, ages 6 to 8.  You will notice some terms overlap.

Middle school age child: grades four to six.

Junior high school: usually grades seven and eight, sometimes including grade nine.

Teenager: age 13 to 19 only.

High school student: grades nine (or ten) to 12.

Girl: any age, but especially to age 14 to 15.  Adult women sometimes talk of their girlfriends and call themselves girls at any age.  

Young woman: generally age 14 to 16 up to about age 20 or 30, depending on who is talking.  Same for young lady, but usually said by a mother when she is angry.  "Young lady [or young man] get in here and do these dishes right now!"

Young man: used by mothers for boys of age 13 to 18 more or less.  College age.

Man/woman: age 18 or above.