Many will answer to start with Python, which is a great start and pretty wise regarding the market. But if i could start with one for the sake of learning, I would go with Elixir. A lot of nice concepts, easy to write and, to me, it is going to be big in a couple of years

First thing: can you already define what would be your main interest ? Back-end development / Front-end development ?

For Elixir, the main reason is Immutability. Functional programming is easy to code AND to test. Having some experience in ruby, I also have to say I really like the syntax. On web part, my guess is Phoenix framework will have the same impact as Rails had in its time. For Go, it is harder to justify this choice. The language just feels right. It is excellent for network and real-time development, is used my many huge company (Docker, Google, Dropbox, ...). Last but not least, Go has outstanding performances.

The correct article is probably this one

I would rather learn Elixir and/or Go right now