I think without the structure of school and the logical instructions and others there learning too and ability to ask questions, etc. that it would be much harder to learn on one's own, especially if you have no previous experience in that field to know how to go about studying the material. Too, I don't think you have been studying the subject for the last 3-4 months? You can't learn a semester's worth of information in just a month or two.

I would not worry about being swamped, not being able to pass unknown exams before you've been given them, I would just figure out in general about databases, learn their parts, look at samples and how they're constructed, etc. but not get into too much detail yet. I am going to be studying databases too, mostly starting next January, I'm looking at this one A brief account of the People in Place history project and admiring it. History, rather than science, but maybe you can find a science project like it?