Let's try
When is the baby's birthday?
Listen and tick.
I have a new cousin. Look at his photo.
He's so cute. When's his birthday?
His birthday is on March 2nd.
How old is he now?
He's fifteen days old.
Let's talk 
When is your birthday?
My birthday is on April 4th.
That's my mother's birthday, too!
Cool! What will you do for your mum?
I'll cook noodles for her.
Chinese noodles are delicious.
Please come then. We can have a birthday party for both of you!
Role-play.
When is your birthday?
My birthday is on January 1st.
That's New Year's Day.
Yes!