Do you really want your child in this ruthless, bruttal industry? It is WORK.
I have modeled most of my life and my 17 yr old models occasionally. She models more now than she did when she was younger... she hated it when she was younger so she stopped. Don't put pressure on your child and if your child earns money... put in in an account for your child because it is your child working.
We are independent and work through companies who do not hire through agencies... aka, non union. We don't model often, it is not our "life" or priority, just a perk.
It can be very rewarding but it is also hard work and lots of rejection. You must have a tough skin because you won't be a fit for everyone and you'll hear no a lot, be around crazy moms who also think their child is the best thing that graced the earth.
That said.. if you choose to go forward... NEVER PAY ANYONE MONEY. You DO NOT need a professional portfolio. Good agencies use uploaded photos to their websites... Kim Dawson, Campbell are 2 in the Dallas area, NY area has already been mentioned... Ford, Elite, etc.
If they like you, they contact you... it is that simple.
I don't know how old your daughter is but casting calls are hard, long, a lot of waiting and time consuming. They are not geared to your schedule.. it could be naptime, meal time, etc.
We don't participate in casting calls.... there is more to life for my daughter and me than to be sitting and waiting for hours on end for a tryout when we could both be doing something more productive and fun. The companies we work with have our pictures, now portfolios, and they call us in for a shoot if someone likes our profile and schedules us in that manner.
Be very careful in this industry