Comedy masks

There were various types of masks in the classic Greek comedy.  The masks with the smiling faces were for the comedies and the sad masks for the tragedies, The actors were chosen by the State, not by the Comic poet.  The poets were using pseudonyms or nick names sometimes.  Aristophanes did so too.

The first three Comedies of Aristophanes-the Banqueters, the Babylonians, and the Acharnians were all brought out in the name of Callistratus; the name of Philonides does not make its appearance until several years later, namely at the Lenaean festival of B.C. 422. Of the eleven extant conledies three-the Acharnians, the Birds, and the Lysistrata-were certainly produced in the name of Callistratus; one, the Frogs, in the name of Philonides; and five-the Knights, the Clouds, the Wasps, the Peace, and the Plutus-in the name of Aristophanes himself. We are not told in whose name the Thesmophoriazusae and Ecclesiazusae were produced.
A scholar said that "For there was a law  among the Athenians, that no person under 30 years of age should recite a drama in the theatre  or speak in the public Assembly. In obedience to this law therefore the poet, not being yet 30 years of age, recited to the theatre through the agency of Philonides and Callistratus the Comedies he had himself composed." Now if this statement were correct, Aristophanes must have been over 30 when, in 424 B. c., he exhibited the Knights in his own name, and over 27 when, three years earlier, he exhibited the Banqueters in the name of Callistratus. But there is no evidence of such a law fixing the age at which, and not before which, an Athenian citizen was qualified to compete at the Dionysian festivals.
Could you imagine Aristophanes taking part in the competition disguised with a tragic mask?