Have granite and love it. Seal it once a year. I really like taking things off of/out of the stove and setting it right on there. This is my second home with it and I won't put in anything different.
If she works greasy dough right on the counter repeatedly it may take a stain. I had a piece that I rolled out biscuit dough on once a week for a couple of years and it took the shortening. It was just a rolling island thing, but now I know. I do biscuits on parchment paper now.
Granite and quartz are both great. About the same price, but granite has more color choices.
They will have to joint it in at least one place. Ask to see what their joints look like. Rocks are rocks, but an installer who doesn't match the glue very well can make the whole thing look like junk.