Going back to College and Online Programs

So Ive decided what I want to be when I grow up I want to be a science teacher... I have an AA in Liberal Arts. Can someone direct me where to go from here? I would like to take some online courses that I can do while the children sleep (next year of course... my life needs to calm down a little) then go to an actual college and do things there when the boys are in school. I am on the 5 year plan. Advice??