Those things don't really sound like they require a web interface, but just sharing of your code. I can easily imagine that building a web interface for a technical program involves several non-trivial steps (especially dealing with libraries), because that's not that common of a combination. I suggest you stick with learning the programming part first and handle the sharing part second. After all, once you have something that works in one language, it's not usually too difficult to translate it into a different language if something else seems more appropriate.

I personally think that Python works really well for technical computing (or for non-technical computing for that matter). NumPy (the array package) is much better designed than other packages in other languages. It's also very easy to share your code (PyPi is the standard place to place your package). So toss the django for now.

I enjoy giving advice on this subject, so feel free to ask lots of questions (if you're interested in the answers anyway).