Annual leave entitlement

Hi, I wonder if anyone can help. i am currently expecting my first baby due Feb 2018. I have let my work know and they have been ok however I do have a question about my annual leave entitlement.

The annual leave at my company runs from January to December. I understand you acquire holiday whilst on Maternity. I was thinking of going on Marernity around January 5th 2018 give or take but i wondered if I would still be entitled to take my 5 weeks annual leave. 

if anyone could help it would be appreciated. TIA