My thoughts.
It's admirable to try and get ahead, but due to the law of primacy, I would be careful about what you study. You don't want to learn something wrong.
Flows- I would avoid doing them now unless you KNOW you are doing them correctly.
Limits- Again, make sure you are learning the correct XJT limits. I'm not familiar with the ERJ side, but on the CRJ side, there were a few company limits more restrictive than the manufacturer limits (such as flaps). Also, understand that there are "boxed" limits that must be memorized.
EPs- usually a little safer to start memorizing the immediate action (boxed), items.
Systems- most airlines have gotten away from the "build the airplane" approach to systems, but it's still nice to have a good working knowledge of the systems and for the most part, they are pretty standard across fleets. Yes, I know there can also be some differences. Know what buttons on a panel do, what it means if a light is illuminated.
Good luck.