How long will it take to make my first sale?

I’ve started bum marketing and so I have 2 questions
Assuming that I have the right niche, how long will it take to make my first sale?
I only have about 4 articles listed on google for my key words so far. Two are on the first 1 or 2 pages for google (for similar keywords) and the others are listed on 3 and 4.
So my second question is how many articles do I have to have published before I should see a sale?

See original post by T.J.