So what makes a provider "Elite"? Does it have anything to do with the quality of service, age, the cost of her sessions or is the title simply one that's self proclaimed? And what if anything makes it better than a provider who charges less?

It is like explaining a diference between high end restaurant and fast food chain.  
BUT there are always an exeptions, of course. I'm not saying elite are always the best.
I had some horable food at high end restaurants and I had some great meals at bachi burger.

I have never found any correlation between "elite" and the quality of service. If anything, because you expect more from "elite"  you are more likely to be disappointed.

However usually elite providers (or any other description of equal meaning) will have great reviews to back up their higher rates if she doesnt then it's buyer beware!

Some elite providers have been miss TER or have some other industry related achievement.

Most are low volume.

But I believe age rarely has anything to do with it.  
Great service is great service no matter what ag