You just say you have so many years. J'ai douze ans. I have 12 years. I am 12 years old.
To say "her age" in French, you would say "son âge".
son age
You can say "Avoir un âge similaire" in French to express "Have similar age."
the Stone Age is called " l'âge de Pierre " in French.
Aucun âge
avoir <age> ans (i think)
Son âge est
gelee
hehe smelly
elle a neuf ans
quel âge avez-vous
j'ai douze ans