Hello. This is Dr. Christian. Do you plan to have her spayed?
Typically these hernias are repaired at the time of a spay surgery at 6 months of age. If you are not planning on having her spayed then 6 months old would be a good time to have it repaired regardless. At that age she is older and better able to handle anesthesia but will also recover quickly.
I've changed to this format from the chat function since it can sometimes have bug issues. If you have any more questions or need clarification please reply back.