Wiktionary
jumping the gun
vb. (present participle of jump the gun English)
Usage examples of "jumping the gun".
I know I'm jumping the gun, but now is the time to reflect, before you're too involved.
I think he's jumping the gun a little - it's a bit early to try for full blown feudalism.
They wore their commo helmets and there was no access to the Swift except past them, but it seemed to Ned that the two men were jumping the gun on their liberty a little.
I've also hired a reliable goon who'll baby-sit him to keep him from jumping the gun on reporting the card stolen.