Things of interest:

Shipping: The mun ships May primarily with Maxie. And understands that given how in the games themselves this can be seen as awkward to say the least given May's age as seen by the average player is of a girl in her early teens. However, that's the reason of her being 'aged up' - although technically the mun sees this as being just as likely as anything else. Although on mun's first playthrough, May/Brendan was just as strong.

Which leads to...

Age:

• May, here, is 20. Technically plus about five months, given the time that's passed since her birthday. She does, however, have a young face, and appears sixteen to most. This is completely realistic - the mun has been told the same of herself.
• Brendan is 22. He's out of school already and helping his father, and it could be assumed he's on an extended gap year.
• Maxie is 30. He appears somewhat older, mainly due to stress and bad sleep habits. (no, you should see his room. it does not escape May's notice that he does not have a bed and makes sure his admins get him one. 'we couldn't argue with her boss she's the hoenn champion)
• Archie is 35. He's known, seen, and treated Maxie as 'younger' ever since they first worked together. The rivalry is still strong... although after the Groudon and almost Kyogre incident, less so. They're able to stay in each other's presence, but will likely start fighting in their own ways.
• Wally is fifteen, and sees both Brendan and May with something akin to hero worship. They aren't that much older than him (smaller than between Maxie and May) but to him, it seems like a lot, and he constantly strives to get stronger to make up for this.

May, prior to Hoenn: 

May had lived in Johto up until the age of twenty. During this time she was schooled, and saw the inner workings of various Gyms due to her father studying how to become a Gym Leader. May had a budding interest in being a Contest star when she was little and watching TV, which faded into residual feelings until Lisia scouted her in Slateport.

May had never had a Pokemon all of her own to train as he'd like before meeting Brendan and Professor Birch.