Horse people - can you answer me this

[Saltire]

After wathcing Ascot I have a question. At what age does a filly become a Mare?
and at which point does a Colt become a Stallion?

A filly is a filly until she is 4, then she becomes a mare.

A colt is a colt until he is four, when he becomes a stallion unless he is castrated before four when he becomes a gelding, so he could be a two year old gelding.

In throughbred racehorses fillies become mares on their 5th birthday (1st January in the Northern Hemisphere) unless they breed beforehand at which point they are called mares.

Colts become horses on their 5th birthday.

They become stallions when they start covering mares.

They become geldings at the time of castration.

Thanks for replies