I haven't researched the issue of older women expecting first children. I know the cesarean surgery rate is sky high, but that is primarily due to obstetric biases. If an obstetrician thinks you are going to need a cesarean, it becomes a self-fulfilling prophecy. Therefore it was a good move on your part to dump the OB and the high cesarean surgery rate hospital. Also, as you point out, the older we get, the more likely we are to develop problems such as high blood pressure that could affect a pregnancy, but age itself isn't the problem. There is, of course, the issue of increased likelihood of Downs syndrome with advancing age, but I'm sure you know about that too.
I think your best bet is to do exactly what you have done: seek out a caregiver whose primary approach is supportive care that facilitates and promotes the natural process and who has low rates of inducing labor (10% or less) and cesarean surgery (15% or less for an ob and 10% or less for a midwife). That way, if an intervention is recommended in your case, you can trust your care provider's judgment. The rest is up to you. Eat right; get moderate exercise; take a good set of childbirth classes from an independent source, not the hospital; hire a doula; and read books, hang out on internet sites, and view media that portray labor and birth in a positive light. I particularly recommend the Giving Birth with Confidence blog at http://birthwithconfidence.blogs.lamaze.org/ and www.childbirthconnection.org. Finally, be prepared to be patient with yourself in labor. Things might take a bit longer than they might have in your 20s. ;-)