It's very difficult to tell. They can make some noises when they eat that could alarm a piggie parent but are perfectly normal. I don't hear anything that would be a cause for concern. Normally, there is cause for concern if there are other factors like crust on the eyes or nose, lack of appetite or weight loss, lethargic, etc.
Still, if you have a thought but she seems otherwise normal, just keep an eye on her the next day or so with a bit more attention.