How long have dragonflies exisited on earth?

Dragonflies are ancient insects. They have been around before the dinosaur's! Some people found a fossil of a dragonflies wing in a coal mine in England. They said it is 3oo million years old!!
Dragonflies have been living since 300 million years ago. Back then, they had a wingspan of 29''!
They've been around for 300 million years, They were here before the dinosaurs!