On the one hand, you could charge a lower rate to start, build a reputation and then eventually charge slightly more than market-rate as a premium escort.
On the other hand, I've found that customers who want a discount are the most likely to be a hassle.
And on the other hand (I guess this must be someone else's hand), you can adjust your rates to experiment and actually see if it matters. You may suspect that you'd attract more business at a lower rate, but you may not. If your income over time doesn't go up with a lower rate, then charge more. No sense in selling yourself short or breaking even on more effort.