You can make something big when young that will carry you through life. Look at all the big startups like Microsoft, Apple, Google, Facebook, Twitter, etc. They were all started by very young people who stumbled on something of unseen value. You'll know it when you hit a home run.
I cannot seriously believe in it [quantum theory] because the theory cannot be reconciled with the idea that physics should represent a reality in time and space, free from spooky actions at a distance [spukhafte Fernwirkungen].