You asked: “How big will the impact of nanotechnology be in my life in the next 20 years?”
Great question and the answer depends on whether you’ll get sick and need nanotechnology. Twenty years is not long. I’ve lived twenty years 4 times over. Each time the situation is basically the same. You are born, grow old, get diseased and die. They have new cures, and new medicine, but you’re still going to grow old and eventually die.
Nanotechnology, if ever realized, will be another medical breakthrough to cure this and that, but you’ll still grow old and die eventually.