What glasses you wear mainly depends on the shape of your face and the color of your hair.
You have gray hair, so I will recommend you to wear semi-rimed or rimless glasses which will make you look confident and vibrant.
If you prefer full frame glasses, full frame glasses with dark colors will look better on you. Never wear bright-colored frames which makes you appear frivolous.
About shape of frames
If you have a round and wide face, you need rectangular frames. If you have a oval face, you can perform well with any glasses.
If your face tends to be rectangular, you had better choose curve frames.
Well, I am so happy that you have such hair because that would make you very special and charming. Anyway, you should know that grey hair are not compatible with vivid colors, for that would make you appear to be a witch or something bad. So you should consider some dark colors such as brown, black or hazel. As to the shape of the glasses , you might want to have a try for black glasses.
You could just choose the black frame of the eyeglasses which could be suitable with your gray hair and your most clothing. You could also choose the white color of the eyeglasses which could to some degree lighten your complexion. You could take these two basic colors of the eyeglasses into consideration. About the shape of the eyeglasses, you could base on your shape of the face to choose the suitable one.