Hi Lubna, it took me about 3 years to go from never having written a line of python before to being where I am now. Which is working as a junior data scientist and able to develop production level data science models. I will soon be putting together a post about my personal journey with more details. Roughly though I would say I spent about 6 months learning basic python before I felt ready to apply anything. I then spent a further 6 months or so on data analysis in Python, another year on building machine learning and data science models. Once I had been working in just notebooks for a while it was not too difficult to branch out into object oriented programming and learning other applications of python. I only had limited time at weekends and evenings to study though so you might be able to progress more quickly with more time.