She goes to 15 classes a week and doesn't do any sparring? What do they do in class that much?
As others have said, you don't need a professional coach for her to go to local competitions, especially as a color belt. She just needs to learn the rules, practice sparring and go try. A lot of tournaments offer poomse (forms) and board breaking divisions, as well. For a lot of kids, it's less intimidating to do those their first time competing anyway.
I'd recommend you start by taking her to a local tournament and see what it's like. They usually have a registration packet available online that explains at least a bit about the rules, and you can ask on here for more info if you want. Once you have a good feel for the tournament rules, you can register her and act as her coach.
I don't know what country you're in, or what organization you want to be part of. But in the US, IIRC, you'd need to be a USA Taekwondo certified associate coach to take her to the USAT national championships, and I think to take her to states once she's 12 and a black belt. Basically that just means you submit to a background check and watch some videos on the USAT website about how to work with kids.