I have been going 9 months and it is only just starting to pick up, and my jobs come in from day to day, i.e. I am not booked up 2/3 weeks in advance like a lot of other guys, which I can live with, as it means I get the jobs from the impatient ones who don't want to wait.
You will run into some obstacles, the 3 main one's I ran into were:
1: Buying a machine from gumtree without knowing anything about carpet cleaning machines, and I was sold it with one broken motor, a pump that broke in a week, and had leaks, as i did not test it first. If you do have to get pre-owned, source it from a cleaning forum member who has a good post count and reputation. The machine i then replaced with the dud one, I got from a well respected member on here, and it has been faultless so far.
2: I hired a website designer to create my website, and went with the cheapest option I could find, which was £150, again off gumtree (maybe I should just tell you steer clear of gumtree haha) anyhow, I found out that the wordpress theme he used was full of adware, and a countefeit download, as you usually have to pay £50 for the use of a premium theme, which meant if I had kept it as it was, my website would have likely had a poor search engine ranking indefinitely. I'm glad this happened in a way, because over a couple of months, i learnt an invaluable skill, making wordpress websites, and I have gotten very good at it!
3: Trying and testing chemicals, and not sticking with the first one, just because you think they can all complete the same results. I'm not saying there are not chems which will be your main "go to" ones most of the time, i'm a big fan of spm and powerburst personally, but what i'm saying is it took me a couple of brands to decide which was best for me.
Lastly, it is the things that go wrong that will shape you as a person, if nothing went wrong, you would not know how to correct it once it does.
As an example, when I was in my teens and early 20's I was motorbike crazy, still am, but never could afford a decent one, so always had to buy bangers that would break on me within a month, but with them breaking on me, i learnt how to fix up bikes, where as if I could afford a new one each time, I would have became a disposable type of person. Now im a bit older, I have a nice bike, and I also have the skills to fully service it myself.
Hope that helps a little.