It can be done, but please note I said no need (the hyphen is required when spelling out the age number as I did). I didn't say wrong. It's a matter of choice it seems in that hyphen application. And the whole posed posting is a matter of style too. In a joke relation environment, the structure passes as is and in all the other ways suggested here. They all achieve the result of getting the point across and that is the basic premise of language. It does have the several noted failings too.
Researching punctuation rules (not grammar which has to do with what form of word to use) I stumbled upon this item in Wikipedia under "Punctuation":Novel punctuation marks
An international patent application was filed, and published in 1992 under WO number WO9219458, for two new punctuation marks: the "question comma" and the "exclamation comma". The patent application entered into national phase exclusively with Canada, advertised as lapsing in Australia on 27 January 1994 and in Canada on 6 November 1995.http://en.wikipedia.org/wiki/Punctuation
And for a guide to punctuation rules (which change as language changes, as evidenced by the patent above) try this
"Guide to Punctuation" by Larry Trask which can be found linked at:http://www.informatics.sussex.ac.uk/department/docs/punctuation/node00.html