Even once you are checked into primary, you aren't allowed to use the sims until you class up.They should just let the new SNA's start using sims if they want to. Idk if they do already but I personally would be there all the time trying to get ahead of the curve for primary.
This is because there's a limited number. Even when you're a primary student, its fighting for scraps to get sim time.
If they bought more, until you know what you're doing, "playing around on the sim" is worth less of your time than you may think. Creates a lot of bad habits bc the Navy wants you to fly their way.