Even if the general impression I received from the play were that Hamlet was a youth of eighteen or twenty, I should feel quite unable to set it against the evidence of the statements in V. i. which show him to be exactly thirty, unless these statements seemed to be casual.  But they have to my mind, on the contrary, the appearance of being expressly inserted in order to fix Hamlet’s age; and the fact that they differ decidedly from the statements in Q1 confirms that idea.  So does the fact that the Player King speaks of having been married thirty years (III. ii. 165), where again the number differs from that in Q1.

If V. i. did not contain those decisive statements, I believe my impression as to Hamlet’s age would be uncertain.  His being several times called ‘young’ would not influence me much (nor at all when he is called ‘young’ simply to distinguish him from his father, as he is in the very passage which shows him to be thirty).  But I think we naturally take him to be about as old as Laertes, Rosencrantz and Guildenstern, and take them to be less than thirty.  Further, the language used by Laertes and Polonius to Ophelia in I. iii. would certainly, by itself, lead one to imagine Hamlet as a good deal less than thirty; and the impression it makes is not, to me, altogether effaced by the fact that Henry V. at his accession is said to be in ’the very May-morn of his youth,’—­an expression which corresponds closely with those used by Laertes to Ophelia.  In some passages, again, there is an air of boyish petulance.  On the other side, however, we should have to set (1) the maturity of Hamlet’s thought; (2) his manner, on the whole, to other men and to his mother, which, I think, is far from suggesting the idea of a mere youth; (3) such a passage as his words to Horatio at III. ii. 59 ff., which imply that both he and Horatio have seen a good deal of life (this passage has in Q1 nothing corresponding to the most significant lines).  I have shown in Note B that it is very unsafe to argue to Hamlet’s youth from the words about his going back to Wittenberg.

On the whole I agree with Prof.  Dowden that, apart from the statements in V. i., one would naturally take Hamlet to be a man of about five and twenty.

It has been suggested that in the old play Hamlet was a mere lad; that Shakespeare, when he began to work on it,[255] had not determined to make Hamlet older; that, as he went on, he did so determine; and that this is the reason why the earlier part of the play makes (if it does so) a different impression from the later.  I see nothing very improbable in this idea, but I must point out that it is a mistake to appeal in support of it to the passage in V. i. as found in Q1; for that passage does not in the least show that the author (if correctly reported) imagined Hamlet as a lad.  I set out the statements in Q2 and Q1.

Q2 says: 

     (1) The grave-digger came to his business on the day when old
     Hamlet defeated Fortinbras: