At beginning of game max level of girls are level 100.
Getting to level 50 give +5 to max level.
Getting to level 100 give +5 to max level.
Getting to level 150 give +5 to max level.
Getting to level 200 give +5 to max level.
Getting Base SED to 1 Mill give +5 to max level.
Getting Base SED to 2 Mill give +5 to max level.
Getting Base SED to 3 Mill give +5 to max level.
Finishing stage 16-9 give +25 to max level. (Not possible at the moment)
Finishing stage 24-9 give +5 to max level. (Not possible at the moment)
Finishing stage 32-9 give +5 to max level. (Not possible at the moment)
Spins and Gacha can raise a girls level to more than level 100, N-Wild, R-Wild, SR-Wild1, SR-Wild3 and SR-Wild5 cant raise levels higher than level 100.