You might be able to get a high enough intellect stat if you do the subject for it, or study every day, or every second day for when it stops. I myself always rotate the classes and don't do the double-stat ones, while slow, it ensures that my other stats are improving. Yet for when the exam and first trial ends, you can, even if you just went full-study, begin doing every other stat for the time between it and the second trial, which should be enough time to ensure you meet some more of the cast, and get it high enough