Once she studies your hair, its condition, its style, its cut, and your lifestyle (e. g., how much time you plan on spending on your hair each day), she will then make some recommendations for color and maybe even a more suitable style for you. Plan on being there for a few hours.
Another thing that's changed from when your mom used to color her grays away under the cover of darkness is the quality of the products available. It's been a long time since anyone has gotten even a whiff of any strong, offensive smelling products in salons. Those have long since disappeared or been replaced by gentler formulations that are free, or mostly free from ammonia, peroxide or other harsher chemicals.