Well, in a nutshell, you can start making money as soon as you know what you're doing. Sounds like a very vague answer, I know. But in reality, anyone who tries to give you a specific answer is just fooling you. In my opinion, plan for at least 6 to 12 months of very focused work.
I recommend getting an in-house writing job at a large company. Or get a copywriting job at an agency. I was looking for a career that I enjoyed, a career where I could grow and a career where I could earn some money. You've probably heard numerous times that copywriting is a great way to earn money while traveling around the world and now you also want to know how to become a copywriter.
Now, the best part about being a freelance writer is that you can work as long as you want, and with more work comes more money. These are customers who not only have the money to spend on great writing, but are also willing to spend it. You can easily earn money working as a freelance writer not just from home but anywhere in the world. One of the biggest mistakes that makes people stumble (and prevents them from earning money) is trying to get writing work without really knowing how to write texts.