I can't say I have such a filling, but in my time, I have probably done thousands of them. The Hygienist isn't qualified to make the diagnosis of a cavity, and prescribe a restoration, although if she is experienced she's highly likely to be right, but your Dentist will make the final decision as to whether you need work now (or later).
Over the years, filling materials have improved enormously, but how the individual lives their life also impacts on the likelihood of any discolouration. By that I mean, smoking, drinking red wine or black coffee, as examples.
Whatever materials are used, the smaller the restoration is, the less chance there is of it being noticeable.