Learning your second language is much easier than learning your first. You'll be more familiar with programming concepts and terms that make it easier to search for how to do X in that language.
Julia is still relatively new and not quite ready (in my opinion) for new programmers. Things change relatively quickly and I think that could add a lot of confusion that gets in the way of learning.
That being said, I think Julia is a pretty great language. I really love the way it has grown and I'm excited to see how it matures.
Data Smart: Using Data Science to Transform Information into Insight
https://www.amazon.com/Data-Smart-Science-Transform-Informat...
All the work is done in Excel. I enjoyed the book quite a bit. Author is Chief Data Scientist for MailChimp.
There's a (very) quick intro here:
http://lectures.quantecon.org/py/pandas.html
You can also look into quantopian for practice, but I don't recommend actually trading money.
Then learn Python, it is mature and has way more study material.
Not to mention Machine Learning libraries like TensorFlow, Scikit Learn & math libraries like Numpy, Pandas, Matplotlib?
Everything there is just set.
I once tried to learn Julia, but the community is just to small to get help at times. It is a work in progress but I recommend you to keep an eye on It.
Conclusion: Think of Julia as a future successor to Python, but not a current replacement.