It does sound like vaginitis, which is treated with antibiotics. But, I would recommend taking her to a vet, as a discharge can indicate a more serious problem, like pyometra (an infection of the uterine lining--this usually requires an emergeny spay). Pyometra usually contains a darker discharge though, so it is probably a simple vaginal infection, like you thought. Also, you may consider that she could be in estrus. I have had some females show a slight discharge when they are in heat. How is she otherwise? Is she behaving normally? Eating well? Pooping?
The Merck Veterinary Manual also says that vaginitis is usually accompanied by an increase in the frequency of uination (just like when a person has a bladder infection).
The decision really comes down to your gut feeling...you know her best, and you know if something isn't right. If she seems off I would take her to be checked. If she seems like normal, then maybe just monitor her closely and see how she does. I always try to let nature take its course before running off to the vet. I don't like to stress my chins unnecessarily, and often their immune system and a little TLC are enough to fend off most illnesses. But the minute I see a drop in appetite, weight, or pooping, off to the vet we go.
I would definitely NOT take her to the vet you mentioned, unless you absolutely have no other options.