Whether or not I'm remembered in 100 years is more a matter of luck than actual accomplishment. I know a great deal about my great-grandfather, who was a man of significant achievement. I'm guessing he didn't think at the time that he was that unusual.
I imagine some of the trees I've planted will still be around in a hundred years.
Whether or not you think you are important, it is useful to come to a belief that you have value simply because you exist, that others have value simply because they exist, and that life is largely what we make of it.