It is کہا in the novel that he is 21. (According to the novel Christine is about this age too, but I think ALW misunderstood a sentence saying "she was as innocent as at the age of 16" that's why she is younger in the musical.)
posted پہلے زیادہ سے سال ایک
Thank you, also thank آپ about Christine's age too, I didn't know that!
