I suggest studying on breeding.
Don't worry. Her eggs wont go bad, she will absorb them or release and eat them.
Comb tail takes a couple generations and ALOT of culling. aka Alot of you dumping money into raising fry before you get ANY returns. I would love to take that on, but I am not that experienced yet. Personally if these are pet shop fish. Which I assume they are. Don't breed them. You have no idea what kind of genetic history they have. That's because the pet shops mass breed for numbers , kind of like puppy mills.
The fry would end up with nasty fins, color and form wise. you may end up with 500 babies that no one will take for free.
Research first, and you'll be able to make a more informed decision on breeding.
http://bettysplendens.com/articles/home.imp
http://bettatalk.com/
Go to those sites and learn as much as possible. Everyone of us had to do it

It really will help!
Don't worry all females get eggy, it isnt a once in a blue moon thing and she will produce eggs all the time. Everytime a woman ovulates she doesn't NEED to reproduce if you get my drift