idiom
don't count your chickens before they hatch
起こるかもしれないことを当てにして計画を立てるな
Meaning
don't make plans for something that might not happen
Example
You should wait until you get the job offer before you start celebrating. **Don't count your chickens before they hatch**.
仕事のオファーをもらうまで待つべきだよ。卵がかえる前にヒナを数えるな。