I found antenatal classes a complete waste of time. I managed to find a good book about pregnancy and read it cover to cover. My lifestyle even 30years ago bore no resemblance to the rest of the class and I didn't even fit in at mother and toddler, I fortunately found a friend with the same passion as me for four legs and we often penned our children together.
I think you have to read any information provided from reputable sources, ie NHS, but also keep in mind that like most of life deliveries sometimes do not go to plan, and that is not a failure, just the way it is. I had to have my first child induced, epidural, then was in hospital for 9 days. The second popped out under her own steam, with just some gas. Each birth was special in its own way.