Back labor Symptoms???

I'm a FTM and I was just curious what symptoms other moms had for back labor? My doctor says I might end up having it since I've had a sciatica and horrible back pain most of my pregnancy (my mom also had it). I know it feels different from regular labor and I'm worried I won't be able to tell the difference in enough time to get to the hospital and still get an epidural. I've been told if you wait to long you may not be eligible for one. Any tips? (Sorry my post is so long).