My cats won't open one of her eyes!

My 1 year old cat won't open her right eye. There is no discharge or redness. When I open the eye all I can see is her eye and something white I am guessing is just part of the eye. It just noticed it about ten minutes ago. Last night she seemed fine. Should I take her to the vet? Or wait a little while?

What you may be seeing is the Third Eye, which usually only shows when the cat is sick.
Is she eating/playing/peeing/pooping normally?
If she is not doing any of these things--especially eating--then I would at the least call the vets.
If she is doing these normally, then I'd wait a night, but monitor her carefully.

Yes she is being her normal self. But is extra cuddly. She now is slightly opening one of her eyes. I think I will wait till tomorrow and see how she is. Thank you for your input!