I am almost 31 and starting back at a university this semester. I was diagnosed in 2007, but I didn't attempt school until about 4 years ago. And then, it was while I was working full time, so only one or two classes to get my associate's and get ready for the university for my bachelor's. I was like you, taking a heavy load each semester. It was hard for me to realize that I can't handle that much anymore, and I had to accept the fact that it was going to take me a little longer to get done. I am currently taking three classes, 10 units. I'm in California, and that still gets me all of my Pell grant, and qualify for the max on student loans if you need that.
I would let your major advisor know, the one who you work with the most. Just go in and explain everything that is going on. I would think he/she would be able to guide you to the right person. I know at my school, you can take the test at another time than the rest of the class and have more time to take it.