Koopa is 4 years old and I’m noticing her beak looks odd... I’m leaning towards taking her in this week to the reptile vet. Have you guys seen this before?
It is split up the middle, and was more than likely pretty painful when it happened, but there's really nothing you can do about it. If you feed her hard things she has to bite then I'd cut that stuff up into bite-sized pieces for a while. Don't make her have to bear down too hard on that beak, to avoid putting pressure on it to keep splitting. That way it will grow back together as it grows.