Variable declarations ... you could go either way. I like that Python is closer to a language that "knows what you mean" even when you don't declare a variable.
You can learn discipline later. Learning to program is a chicken and egg problem, you have to learn two things: a language (any language) and programming concepts, and unfortunately you have to learn one to do the other. Python's forgiving nature makes that a bit easier than some other languages.
The point is being made that learning one language makes it vastly easiest to learn another , so you may as well start by learning one that is designed to be learnable rather than necessarily one that is in demand.
The biggest challenge for Windows users is remembering to go to python.org and not python.com to obtain their version.
Plus your going to at least want to install a better text editor and probably set some environment variables.
The installation process for all of these things shouldn't be a big hurdle since all you'd have to do is follow a set of steps that can be easily demonstrated.