Our previous understanding was that The Avengers takes place in 2012, which if true, would place the events of Spider-Man: Homecoming in 2020.
There’s nothing inherently wrong with this, except that we also know that Homecoming takes place more or less immediately following the events of Captain America: Civil War.
This would mean that Civil War must also take place in 2020.
In Civil War, Vision makes reference to it being eight years since Tony Stark revealed himself to the world as Iron Man, which means as of Civil War, we’re only eight years into the entire MCU.