I'm a high school Special Education teacher who would like to develop an online educational game for students with disabilities. My current tech skills are minimal. Since my idea is in its infancy, what skill set do I need? Should I take game design classes?
Its not clear if you intend this game to be a business or a hobby project (and there is nothing wrong with that - it's a great way of learning something new).
If you intend to develop this project as a business (very very hard to be successful in games IMHO) then start with the business side - who is your customer, how will you find them, what will they pay for etc. If you intend to work on this project as a hobby, then skip this part.
Then I would, personally, start with basic programming skills before looking at anything specific to games.