welllll i'm going to be honest.
with my first, "crowning" took.... ohhh it must have been close to an hour, if not more so (i pushed for several hours). and it HURT. it felt like i was on fire, and being sliced up with razor blades (and i tore very, very badly). he wasn't even a large baby.
with my second, "crowning" took a very short time ~ less than 5 minutes ~ with no tearing, and still hurt almost as much as my first.
i think there's a lot of misinformation that gets spread around about crowning, maybe because women honestly don't remember but also maybe because people don't want to say "oh yeah, that hurt like a mofo' SOB" ~ because let's face it, that's scary. it's scary to know that you'll have to deal with that level of pain, that sort of intensity that you have never faced in your life, and the TYPE of which you'll never go through unless you give birth vaginally. and for some women, there IS no pain, there's just pressure. for some women, birth is orgasmic.
but for some women (eh hem, like myself) it's one of THE most painful things in the entire scope of human existence.
someone here said (and i'm paraphrasing) "oh yeah, it hurts but it's over in a snap" ~ well, no, it might take a really long time. or it might be quick.
what i *can* tell you is that POSITION and RELAXATION are the two biggest factors. if you fight it... if you back away from it psychologically... it will take a really long time, and hurt, and you'll probably tear. but if you accept it, if you roar through it and just take it as it comes ~ you'll be fine, it will go smoothly, and you'll have far less pain and a much lower risk of injury.
i was terrified of it too, before i had my first. and then, after i had my first, i was terrified of it even more.
but after my second it was... completely transformative.
i guess what i'm saying is: yes, there is the potential for great pain. but your body was built for it (whether you believe in creationism or evolution, there is no denying the fact that women's bodies are perfectly designed for the work of birthing babies). you can do it.
believe in yourself, believe in the baby, and take each moment as it comes, and you'll be fine.