I recommend going grey as it sounds like you are ready to take that step. Do this gradually with your hairdresser. Grey is actually very fashionable at the moment, so you will be perfectly on-trend!
You are also very lucky to have curly hair – so make the most of it! If you feel that your bob is boring (although I think they are gorgeous), I would embrace some layers to give your hair lots of movement and volume. Keep it above the shoulders so as not to drag your face down and to keep it fresh and modern.