It took me about 10 months to become half decent at drawing.
I could always draw ok but hadnt done it for over a decade, i decided to give it another go in 2014. I watched a lot of videos on youtube of people drawing to give me an idea of where to start and what to do. I bought some cheap pencils and paper and went for it.
Its a very enjoyable thing to do as you are creating and learning as you go along, i would recommend giving it a go if you think you have an interest.