If her hooves are in good condition, and handle whatever she's doing already without, then by no means does she need shoes.
All five of mine are barefoot. My gelding trips horribly with shoes. For that, he can't have them on for any amount of harder work, and thankfully his hooves are strong enough to handle it.
The only times he's had shoes on, is when we travel into a rockier terrain and I don't want his hooves to chip, or if it's raining a lot, and his hoof wall starts cracking. Otherwise, he moves his best without. Why spend the extra money anyways if they don't need them?
Why are you thinking of changing from Bare to Shod ? Just because someone else does, does not mean you need to as well..... only 3 of my horse's are shod and the other 3 have wonderful hard, wear them down evenly hoof's. JMO 2cent's ...
Horses who are heavily competing on show circuits or have to deal with really rough terrain (lot's of road work) are pushed to have shoes on so it prevents hooves from wear, tear and breakage as well as supporting and securing horses on their feet (corks, studs etc). If your horse has never had shoes on and if completely sound I wouldn't suggest getting shoes put on. If your horse isn't chipping and has a proper bare foot job done, it should be happy enough without.