The question 'Quel age as-tu' asks How old are you. In the word-by-word translation, the interrogative adjective 'quel' means 'what, which'. The noun 'age' means 'age'. The verb 'as' means '[you] have'. And the personal pronoun 'tu' means 'you'.
How old are you?.
The phrase, Tu a quelle age? means, what is your age? in french.
I would say, J'ai 11 ans, because i am eleven. If you cant understand what it says, you pronounce it like this,...