So long as you're happy. Another idea is maybe that the bow is a powerful magical weapon that belonged to her grandmother and her grandmother was someone super-famous and Katarina has no idea? It could give Pyromancer something to work with and the bow could reveal additional powers down the road. Hmmm... maybe the spirit of her grandmother lives in the bow itself which is why it's so easy to use?

I once had a character who was a young girl who inherited gauntlets that granted her immense strength. (Girdle of Giant Strength for anyone with D&D experience) She carried a normal bastard sword, wielding it like it was a two hander but what I really enjoyed was the look on most warriors when she, quite literally, twisted their arms.