Heyyy I'll be 20 when I go to the WC too
I have no idea how much it'll be but I'd save about 10 thousand at least, because tickets for each game are very expensive and the hotel and air... it's all very expensive. I'm going to get a job at a big airline so I can get free flights there (hahaha I'm smart) so maybe you can try to get a job at a big airline just before?