Lessons for my daughter?

My daughter loves horses....like, adores them. I have been wanting to get her into lessons but couldn't until her "bio mother" lost custody, because she wouldn't consent. Well, I finally fully adopted her, and her dad and I finally got her enrolled at a stable. My question is, what will she need for the cl? Like where can I get boots, breeches, her helmet, yatta yatta?! I need help! Thank you!!!