[M_O_B_B_S_T_E_R]

Yes you have to wait until you reach a 100 percent in order to level up. If you race somebody your same skill level but with a lot higher networth you get a lot more exp. So you could be racing 20 times and get very little exp and somebody else could just be racing once and getting as much exp if not more than you. So it all depends on who you race. But theres no way to level up without reaching 100 percent.