And not just tested for one sale. You need to make multiple sales before your sales are anywhere close to relevant. If I were you, I would give the ad spot to several escorts for free for a month. 4 or 5 different girls. Maybe even do a second group for a second month. Then you have some useful stats, and a bunch of girls who have seen the worth of the ads. You lose two months, but in really, what is two months in the grand scheme of things given what you get in return? You get solid data on your site, what the ads return for the buyer and potentially 4-10 customers already signed up. You will know if you are on the right track, what to charge, where you need to make improvements (other than the obvious- get more traffic)
best of luck.