
Hi Danielle.
8 months is fine for a first season, usually any time from 6mths onwards. You don't need to do anything except keep her away from the boys! :D
Her behaviour could well change, snappiness with other dogs, moody, depressed and a whole host of other things too.
I have not heard of one go off her food, others may of though, but if she is normally a good eater and has for no apparent reason stopped eating, if she were mine I would ask the Vet to give her the "once over" just to make sure she is well in all departments.
Dawn.