Jump the gun
Meaning: to do something too soon, before you have thought about it carefully, to start before the starting signal. (Originally used in sports contests that are started by firing a gun.)
Example: We all had to start the race again because Jane jumped the gun. When we took the test, Tom jumped the gun and started early.
Выучи грамотный разговорный английский до уверенного владения всего за 9 месяцев по системе естественного усвоения иностранных языков. Жми!
Example: We all had to start the race again because Jane jumped the gun. When we took the test, Tom jumped the gun and started early.