I'm kind of in the camp of people who say this is a useful person to bounce things off. She is being devil's advocate - that's ok. Understand that. Understand that she is less risk tolerant. But also understand that you have to have answers to the fundamental problems before you start.
Are these "you might go to jail" problems, or are these "you might not make money as fast as you hope" problems? The first need addressing pronto. The second are over-worries.
If you compete on price you will lose. It's true in almost every industry.
I would focus only on upper middle class people. They will pay well for good service, which means show up when you are scheduled, clean everything, don't break anything, leave them alone.
And while they have money, many are still looking to save where they can. So offer them one free cleaning for each client they refer, but make it a caveat it has to be someone in their neighborhood. That way it will be a pricier job and be someone in a similar payrange.
Competing on price is the worst thing you can do, so never do it.