Au Pair Agency

We've made up our mind. Mark and I want to host an au pair in our home next year. It would make so many things easier for us. Until now, we've rented out a small 430 sq ft attic apartment. Our tenant is moving out in November. She's heading back home to Chicago.
That gave me the idea of bringing some help into the house. Our three children, Julian, Justin and Julia, are now 12, 9 and 6. I work as a freelancer from home, and so far my mother Elaine has been a great help. But this year she had hip surgery and has to take it easy. The time when she couldn't lend me a hand wasn't easy for me. Sometimes I was at the end of my rope. The kids have tutoring, tennis, piano and soccer, and some of the time they need to be driven.
I definitely need an au pair with a driver's license. Is that even simple to arrange? Will she be allowed to drive in the US at all?
How Do You Find the Right Au Pair?
Just searching online doesn't work! It quickly became clear to me that an au pair agency is the only sensible way. But which au pair agency is right for us?
I'm trying to go by these criteria:
- Choosing the right country
- Amount of the agency fee
- Friendliness
- Professional expertise
- References
- The au pair agency's experience
For me, it's especially important that the au pair agency has been around for at least 10 years. I don't know whether that guarantees a good au pair. But if an au pair agency has only existed for three years, I'd be rather skeptical.
My friend Melanie says I'm being too strict. Young start-ups in particular are more motivated and especially keen on good references. That's an argument, of course, but as a Taurus I'm just a bit too square for that. Or, as my friend puts it, a bit old-fashioned in my clothing style, too.

Finding the Right Au Pair Agency Is Costing Me Sleep
I really imagined this would be easier. I never expected so many appealing agencies. Many make a very competent impression. But how do I find the au pair agency that's right for me?
I'll probably send out a mass inquiry and judge how the agencies are set up by their response time and the answers I get. A quick response time is important to me. An agency that cares about this could be the right one for me. In my job, speed matters just as much, and it's become second nature to me.