it means "which" we use it for a "male"

It's closer to "which", and matches with male nouns. "Quelle" is the female gender. "Quel chien?" = "which dog?" ("chien" is male gender) "Quelle espèce de chien?" = "which(what) kind of dog?" ("espèce" is the female gender)

means "what" Quel age as-tu?= how old are you?

mainly it means which, but sometimes it means "what" for instance: quel heure est il? = what time is it? or quel est ton nom=what's your name?, quel age as-tu? litterally means: what's your age? P.S quel est pour le masculin, pr le feminin: quelle