Don't count your chickens before they hatch
usiseme umemkamata kuku kabla haɟataɡa jai
In Swahili Usiseme umemkamata kuku kabla hajataga yai.
This proverb is a direct equivalent, warning against counting on something before it's certain.
Example
"Alikuwa anasherehekea tayari, lakini nilisema, 'Usiseme umemkamata kuku kabla hajataga yai.'"
