Fortnite season 3 challenges?

I do not want to spend a lot of money in fortnite… Maximum 10 euro for the battlepass… (I've already done it for season 2) Now I wanted to do it in order not to get any vbucks losses, so that I only buy the respective battlepass when i have my vbucks get out again… Stop without losses… However, in order to reach a certain level, for example in the 2season it was level 63, I have to do challenges or missions. I wanted to ask if the missions are possible before I buy the battlepass. Do you know if that would be possible?

Become level 100

Yes, I also thought about it, but for h missions it would be quicker, so I would have the rewards faster, but otherwise it will amount to that