Can anyone tell me how to become a blockchain developer?

Yes, Facebook has a large database of users and the huge money to invest in the cryptocurrency world. A Facebook Spokesperson said:
“Like many other companies, Facebook is exploring ways to leverage the power of blockchain technology. This new small team will be exploring many different applications. We don’t have anything further to share.” Facebook can integrate his cryptocurrency into Facebook apps.
It will be big news if it appears to be real and if Facebook is serious about launching its own Cryptocurrency. A “Facebook Coin” will be having the potentialities of becoming the premier cryptocurrency with a huge number of active users.

Maybe or may not be. But ETH is my favorite cryptocurrency. The smart contract is the best feature of Ethereum technology.