User blog comment:OneofthePendragon94/The age of Merlin, Arthur, Morgana and Gwen./@comment-92.9.169.138-20200728092729

Wow. This is complicated. I'd say that Merlin is 17 in S1 (which is REALLY young to have such a great destiny) 18 in S2 (Because I read somewhere that there was no gap between S1 & 2, and I'm assuming each season lasts a year) 20 in S3, 22 in S4 (which makes sense as they refer to him as a man, which he presumably became in the gap) and 27 in S5. Arthur everyone agrees on. 20 in S1 because he became crown prince, and 30 by the end, which is a sad age to die. Morgana HAS TO BE OLDER THAN ARTHUR TO HAVE A LEGITIMATE RIGHT TO THE THRONE. How much older is a mostly a guess, unless anyone has any ideas. Gwen is also a complete guess, but I think she would be younger than Morgana and Arthur, and around the same age as Merlin, maybe older.