With the recent advancements in the field of Data Science, tons of resources are available online for students who want to pursue their career in Data Science with Python. It is one of the most used programming languages. Tons of MOOCs, online courses, Books and PDFs are available from where you can start learning and coding on your environment.
There is no answer to "How fast". It depends on 200% on you. It is on you that how fast can you grab this programming language. If you have prior experience in programming before like C or C++ then it won't be an issue to take up this language. It has got easy syntax, coding is really efficient and the learning curve is not steep as other languages. You just have to practice a lot as without that you are unlikely to pick this language strongly.
If you are a beginner and want to know more about Python programming language then do refer the following video tutorials:
If you want to know more about Data Science then do check out our Data Science Online Courses which will help you in learning Data Science from scratch.