I would like to say that you were both very wrong about how nothing you do now will impact the world in the future.
In 3500 years you will without a doubt be forgotten but indirectly you will have changed the world so much, if you were stopped at a red light today then the world will never be the same. It will slightly change your actions later that day, which would change your actions the next day and so on, now this change in what happens will change other peoples actions by changing their day, so they then carry on this slight change in peoples actions and changing the time at which events happen.
This slight change in timing will have the biggest change, eventually it will affect contraception, so someone who would've been born is now not born because actions are changed, this starts the big chain reaction because it will change everything. Every action and everything this person might have done is now no longer going to happen, and vice versa someone who will now be born is going to change everything, it's all just a big chain reaction that gets bigger and bigger, this chain reaction will eventually reach 3500 years from now, so yes you will have a ridiculously large affect on the future all from a tiny action.
And think how many of these chain reactions are set off. sometimes even bad things will lead to brilliant things happening, and good things happening will lead to bad things happening. If something like this had changed where Hitler was standing one day when he was about to go into a battle during WW1 he might've been shot and killed. He was shot, if it had just hit him in a different place he might've died, if this had happened there would be no WW2 with him leading it, you would never have been born, I would have never been born, maybe there would never have been a WW2 maybe there would have been more world wars, either way the world would be completely different, in some ways better and in some ways worse, overall it's impossible to know.
Basically you're wrong on your insignificance in this world, I doubt you'll even read this either way it will change the world, and it's going to change mine because i'm now 30 minutes late to watching House of Cards.