She actually does have some familiarity with firearms.
She lost her genie powers in the 2nd game, taking on Risky's moveset in a bid to restore them.
That doesn't need to be spoilered, it's the basic premise of the whole game, and is literally the game's synopsis on its Steam page.
Besides, that "familiarity with firearms" only involves a flintlock pistol, an entirely separate beast from a modern rifle, and a ship's canon she uses to double jump.
