idiom
don't count your chickens before they hatch
no hagas planes para algo que podría no suceder
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**.
Deberías esperar hasta recibir la oferta de trabajo antes de empezar a celebrar. No cuentes los pollos antes de que nazcan.