In order to get the right fit, go to your tack store and ask for an employee to help fit you and your daughter to new helmets. It might take a while, it did for me, but I ended up getting a helmet that I love. I have the Charles Owen JR8 and it fits beautifully, looks great for shows and practice, and is worth the price. I did use a coupon, but still! And since I use the helmet for both practice and shows, I use a velvet helmet cover I used when I was younger when my helmet wasn't velvet to protect it. Safety is so important, you can't just order a helmet online and hope it fits. You need to go to the store in person and try on as many as needed until you find one that fits properly. Also, don't give up on brands because they are known to have one type of fit. I tried on a couple of Charles Owen helmets, and other brands, but the best helmet that fit me was actually a Charles Owen, and they are so comfortable.
Also, I do not know how old your daughter is, but if she is younger, maybe you should consider helmets with the dials in the back to adjust the fit, especially if she has a lot of thick hair.
Good luck on your helmet search! :)