[quote=Griever]
Isn't Dany like 14 in the books?
[/quote]

Depends on which book. I read somewhere that Martin said that the first was six months time, and the rest took about a year each (apart from Book 4 and Book 5, which have some overlap).

So by the time she gets her army, yeah, probably 14. Though the show has aged characters by about 2-5 years.