We are a group for adults in the midst of a fan-site that is intended to be family/kid-friendly, for a family friendly game, and we want to do our best to ensure that the group is serving it's purpose, which is to connect adult players. It is actually for you as we gain nothing from doing this except knowing that we are making people happy to find other adult players, especially if you enjoy Central and want to play with other adults.
Additionally, this makes it easier for us to keep track of what's going on with requests to join (since we tend to have a high volume of those), gives you a record of your request, etc. As stated in another FAQ answer, we cannot see or hear you and the chances are probably slim that we know you. We don't ask (and have never asked) for any official forms of ID, so our tools for determining your age are limited. We don't think having a brief questionnaire be filled out is too much to ask.