You have reported bilateral foot swelling without recent trauma but remote history of ankle trauma and hairline fracture.
It does not seem that the old injuries are the cause of the problem since both feet have swollen at the same time.
I also assume you are not pregnant which can cause swelling.
Other areas to consider are:
kidney and liver problems
circulatory problems in the legs
heart failure (unlikely in a 26 y.o. female without cardiac history and no current symptoms of shortness of breath, chest pain, or irregular heart beat)
At other times we do not find a cause and recommend exercise, salt restriction, and leg elevation.
Your family physician can take a thorough history and do a physical exam and order some blood test, urine analysis, x-ray if needed, and doppler ultrasound to check leg circulation if needed.
Take care and let us know how it goes.