I'm taking my son (12) to get braces this morning. Our dentist didn't refer him to an orthodontist until he was close to losing his last baby tooth, and the orthodontist specifically waited until after the last baby tooth fell out.
My son also has friends who have had braces as young as 8-ish (not vary many, but it's not unheard of). And as other have stated, those kids often need a second round once the baby teeth are all gone.
Over the next few months, my son will get uppers and lowers, plus the equivalent of internal head gear. He will likely need wear them for two years, after which he will probably be fitted with a retainer.
The cost is $6k flat, all inclusive, regardless of whether we use insurance or not. I'm not enrolled in a plan that covers orthodontic work, so I'll opt to do a payment plan that allows me to utilize a limited purpose FSA and save the money tax-free. The office has been more than willing to work with me to figure out a payment plan that lets me maximize this benefit, but they have never waivered on cost.
I'd get a second opinion, for multiple reasons. As others have said, the orthodontist shouldn't charge you anything for a consult.