Here is just my take:
I would suspect most places MUCH prefer 1-2 years' acute care experience, meaning HOSPITAL INPATIENT NURSING experience. I personally think med-surg, ED, and ICU/CCU nurses make EXCELLENT OB nurses. So, often, do prior nursery or NICU nurses. And post-partum is a very logical first step, if you can get a job in such a unit!
Office/clinic experience alone, while really valuable, it not usually sufficient for most OB nurse managers to consider a candidate for L/D nursing in their departments. Really, you want inpatient acute care experience. It helps you learn to prioritize/organize your day and care of patients, teaches you how to "think on your feet", handle emergent medical cases as they come up, and function efficiently and safely in the hospital environment.
If you can get a job in any acute care area of the hospital, especially, med-surg, ICU/CCU, ED, etc (and yes, they do hire new grads or people out of the hospital for a while, in some of these areas, as well as some in OB) then that is a good thing. IF you can secure a job in OB right out of school, that is good *IF* you have good and thorough orientation and preceptorship or residency (at least 6mo to a year is best, for new grads or people with zero OB experience)----then go for it.
And yes, having taken NRP and FHM classes may be very helpful. However, I don't expect FHM classes to be too useful for you unless you're working in OB already. A lot of it just would not make sense. Being an AWHONN member, IMO is a plus, also.
I hope this helps.