Hello I am 32wks pregnant and will have child end of March. I was wondering when I should file my taxes to be able to claim dependent?

Any time after your child is born, but you will only be able to claim him/her on your 2024 taxes next year (not in 2023).  

Congratulations!

You can file your 2023 tax return any time since you cannot claim a child on your tax return until it is born.  Since the child will be born in 2024 you can only claim the child as a dependent on your 2024 tax return that you will file next year in 2025.

If your child is born in 2024 you can not claim a dependent on your 2023 taxes. Only on your 2024 tax return and following years.

@DoninGA 

Did the GA unborn credit end?

@ee-ea No, The Georgia state program still has the Unborn Child exemption.  Since the OP did not mention a state the answer was generalized.