With regard to age, a Playable Character (PC) should be at least eighteen. The game is taking place during the start of 2038, so when picking your character's age be sure to use the corresponding years. If a character is twenty-seven, use the following method; 2038 - 27 = 2011. Please see the Game Day Settings at the top of the page within location-based forums for the current in-game date.
Also note that a member's character limit is staggered based upon activity and the current number of playable locations open on the board. Playable locations are defined as any Earth location and the Otherworld. If you have any question about your activity level affecting your ability to take on additional characters, then message a staff member directly to ask.
After 6 months (or 180 days), players are eligible to join the Writing Staff and play any number of assigned NPCs. These day counters are based off of a player's first in-character post and rely on a player's continued activity.
Please be sure to register any new characters under their own account. The jcink forums allows you to link accounts together. This enables you to switch between character accounts with the click of a button.