Yes, there are quite a few. I have long-standing UTI issues, and don't want it affecting my kidneys, so I try to stay on top of it with staying hydrated (with water - sugar is inflammatory) and taking herbal remedies. Until antibiotics replaced everything in the 40's doctors always prescribed UvaUrsi to treat UTIs.
Not sure what you have for retail stores, but you can also go online to The Herbalist which sells a line called Bladder Be Well, consisting of a tea and a tincture that are safe to use everyday for upkeep: https://www.theherbalist.com/body-systems/bladder-kidneys...
Also, a place like SuperSupplements will have UriActive, or you can get it online at Vitacost: http://www.vitacost.com/Lifetime-Uri-Active.
These things might not be "approved" for children, but no herbal supplements are, and there are plenty of things the FDA approves that are junk, in my opinion, so I don't stake much claim in that label. If you talk with an ND or a pharmacist at a natural remedy pharmacy they'll tell you that it's much safer to take herbal supplements that help rather than wait until you've got and infection and then take an antibiotic that kills off all the good bacteria in your gut, thereby making the bad takeover and the cycle starts all over again.
You can give her these herbs if she's bothered with UTI symptoms, but the best thing to do each day is keep sugar and processed white flours out of her diet and keep a water bottle with her name on it around that she can always grab and drink from. Probiotics are good for her to have everyday (Jarrow makes good ones), either in capsule form or sprinkled on her food. I do this for my girls.
Finally, it shouldn't be common for a girl her age to be getting a lot of UTIs, so make sure she's always wiping well, and from front to back. Explain how the bad bacteria from her rectum will get into her urethra if she doesn't stay clean. Moist wipes might help until she's a little older. Also, make sure she's keeping her underwear dry. One of my daughters did the playing-too-long thing, and would have damp panties during the day which led to a near-infection (but we caught it, and treated her with the herbs, and in a day she was feeling better).