Another American here, I think it's important to be aware that those attacks happened as a direct result of evil -empire level shit the US is responsible for in the 20th century.

I was an adult when 9/11 happened. After growing up in cold wars, Gulf wars, recessions, etc. that day was extremely horrible, but also felt like just the latest big symptom of an ongoing downfall.

My parents' generation had the Vietnam War as their One Big Important Thing, their parents had WW2, etc. Like other commenters are saying here, what seems like the One Big Important Thing to you is really just a matter of where on the running timeline you happen to be. I find the best way to gain perspective is to examine and understand the entire thing, that's the only way I think anything constructive can be done about any of it.