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 Those have long since disappeared or been replaced by gentler formulations that are free, or mostly free from ammonia, peroxide or other harsher chemicals.
Is your hair healthy enough to withstand the chemical onslaught some coloring products produce? Or could it use some TLC before you step up to a new color?