I teach OB part-time for an RN program here in Ohio. I hope you find your experience exciting & full of learning opportunities.
Hopefully, you will be able to see a vag & C/Section delivery!! However, I would guess that most of your time will be spent in PP & Nursery, because that's where LPN's are utilized most often.
Tips...take a little notepad in your pocket & write down anything you have questions about (during report, listening to other nurses talk to each other, assessments, etc). Then, when there is time, look things up. You could always ask your instructor or staff (if they're approachable).
Also, go in with a non-judgemental attitude. In my experience, I've noticed OB has a very diverse client base (culturally, socioeconomic, etc...).
One more thing...remember to speak to your patient in their terms. In school, we try to be so professional and proper that sometimes our patients don't understand what the heck we're saying. Kind of defeats the purpose of good communication...pet peeve...don't ask them if they're burning when they void...urinate is fine...heck, pee is ok too, esp. if they're young, or if you feel like they're "not getting" other questions! If you tell them you're going to assess their perineum, they'll probably look at you like you have a third eyeball growing on your forehead..
Hope all goes well for you!!!!!