Delayed FMLA

I am pregnant, due in March 2009, and I have not been employed at my company for 12 months yet (I started June 30, 2008). I have asked if I can wait and take FMLA leave in July once I qualify, even though my child will be born in March, but was told by the HR representative that I can't do that. I have tried to research the law, and according to 29CFR825.201, FMLA leave must be concluded within 12 months of the birth of my child, but there is no other information about taking a delay before going on leave. Is it legal for my company to deny me delayed leave?