That's a hard task and a tough goal to have. But with enough dedication and of course passion, you'll be reaching your mastery in a year.

So first, better have an idea on basics of blockchain technology, then how it works, its advantages and disadvantages, up until you go to some intermediate to expert course in building a blockchain. But to succeed with that, you should also consider taking courses with programming, data management, networking and software development as well, and add some background ideas with trading and the market and how does it work. Yes, sounds too many to take, but like what I've said, it takes dedication and passion.

My suggestion would purely make you a Full-Stack developer once you've mastered all of those. But if you just want to make a simple crypto, blockchain and ERC20 system is enough, but I assure you that there would still be a lot of loopholes if you wouldn't take a consideration with other aspects that affects your crypto.