It depends what strain of cat flu the cat has. Herpes or Calici. Although the cat can rid itself of calici one day it may come back if the cat get's pregnant it is a risk I would not take. A breeder told me of how she bred a cat who had had cat flu for the whole litter to die from it. Why take that risk?!

I had the Calici virus in my house and it cost a small fortune to test every single one of my cats to see if they had it. Luckily no one did except for the carrier. My cats were very lucky. The carrier has since been rehomed to my nan whereby he is no longer stressed out and is clear of all symptoms, though may still carry. He is also being fed an excellent raw diet and i've never seen him look so healthy.

I then gave all my residents a course of antibiotics (another small fortune) and deep cleaned my entire house and threw out very expensive scratch posts (just in case) and bought new ones and all new beds, food bowls, cat carriers.

I am just saying from experience I would not breed her but then only you can decide that.