Truthfully, I like her a lot. She is what a good QH should look like; her legs are good, her angles are good, and I just like her look.
Just make sure that you are prepared for all eventualities in the breeding/foaling part of it and make sure that you either know how to train a foal properly or plan on getting some help.
Go ahead and get her vet checked and if the vet says she's good to go, give it a shot. With her last foal being several years ago and with her being the age she is, I'm unsure if she'll take even if she is healthy enough to carry, but IMHO, it would be worth a shot.
Just make sure to pick out a good stud that will compliment her well.
As long as the vet okays it I don't think it would be awful, but personally I would be hesitant. My old horse was a TB and had been a brood mare for years, and produced 5 awesome foals that did well on the track. We are good friends with her old owners and he called us when she was 20 asking if he could breed her one last time. We decided not to let him because we were riding and showing and doing well, and let me say I am happy we didn't. A year later when she was 21 her kidneys failed and she sadly passed away. Yes horses can and do live well into their late 20's early 30's, but they don't always make it long, you just never know.