When is it too late to request an epidural?

I've always given myself a jumping point. I try to wait until the pain is "5" or worse, or until I am 4 cm dilated. But, that's only because I'm scared I'll have to poo and won't be able to walk...lol! Don't be afraid to ask for one when you need it...even if you are just starting your labor. You just go off of what you can handle...don't try to be Super Woman! Good luck! :)