The "be" verb can be confusing. Let's study a little.
About yourself
I am ten years old.
I am happy today.
I am hungry now.
About a boy or a man. His name is Jack.
He is ten years old.
He is happy today.
He is hungry now.
About animals. It is a dog.
It is ten years old.
It is happy today.
It is hungry now.
About objects/things, not people.
It is a nice car.
It is a good game.
It is a fun sport.
About a girl or a woman. Her name is Jane.
She is ten years old.
She is happy today.
She is hungry now.
About two or more other people.
They are ten years old.
They are happy today.
They are hungry now.
About you and people together with you.
We are ten years old.
We are happy today.
We are hungry now.
You are ten years old.
You are happy today.
You are hungry now.