Absolutely not. Having only first and second year under your belt isn't enough to really start studying for the NAVLE (with the exceptions of Mizzou, Mississippi, and U. Arizona as they start true clinics third year and have finished their didactics). You haven't learned all that will be on the NAVLE by the point.
I "started" the beginning of fourth year, which is March of third year at my school. I bought zuku for cheap at that point. Then promptly didn't do anything with it till August. The norm seems to be starting between 3 and 6 months prior to your exam. So that's May of fourth year at the earliest.
Another way to think about it: your didactic years are already study sessions for NAVLE because you're learning the information for the first time in lecture and then studying it for your regular curriculum anyways.