Age & Time
From Radiant Heart MUSH
Time on RHM is not a fixed thing. In general for ease of setting you can assume it's vaguely the same time in-game as it is in real life - if it's December IRL, Christmas can be coming up in game. This is to simplify things and prevent people from talking about snow in July. But, much like in anime and shows, time exists to suit the story, not the other way around. We're trying to avoid having people feel closed off by time; time should be an ally, not an enemy, to storytelling.
Can you have your character age and grow? Yes, but try to keep with your cast if applicable, and don't have more than one birthday per real-life year.