I think yesterday was when I realized I shouldn't be a mathematician. I was at the grocery store, restocking for next week. I had bought around twenty items, and thought I was under my budget. When I went to check out, I was ten dollars over!
Available choices:
 * I then realized that I was not good at math.;
 * Then I knew that I was great at math!;
Which option is the next sentence?
I then realized that I was not good at math.