Most games that students play have progressive leveling whereby the level ups are easy to achieve at lower levels and much harder to achieve later on. It's used as a hook to allow players to experience early success before grinding for bigger rewards later in the game. I simulate this by having a random event that causes the level up cap to increase throughout the year, but doing it this way disadvantages students at lower levels who need to earn markedly more XP than their class mates had to to achieve the lower levels.
Ideally, being able to embed this into the rules at the start of the game would be a really helpful feature. For instance, having the threshold for achieving level 1 as 200XP, but then having 2000 XP needed to to progress from Level 9 through to Level 10.