Want to try and use Python and (if you need it) IRAF? Try
installing AstroConda (click here)!
If you need to learn Python, I would recommend Codecademy. They offer sessions where you can get a feel for the language. Codecademy also offers learning sessions for other languages as well (e.g., HTML and CSS).
Why learn Julia? Basically, Julia is very similar to Python that it is easy to use, but it is almost as fast as C or Fortran. Check out the comparisons in speeds here or here. If you want to start learning some of the syntax really quickly, try looking at the following links:here!
My favorite text editors
If you want to start learning how to write scientific papers, eventually you'll want to use LaTeX to do so. For starters, I recommend using Overleaf (click here). There, you can find the latest version AASTeX and start practicing some LaTeX.