first off, is the egg turner still in the bator? if so it shouldn't be, on day 18-19 you're supposed to take it out, however, opening up the bator is a big no-no so if it is still in there, i'd turn it off,
also, considering that this is your first hatch, i tend to doubt that it's you, the chicks can break through an egg shell, they should be able to break through the sack, my first hatch i ended up by only 12 hatching out of 20,
i ended up by helping 3 out of their eggs because some were hatching from the wrong side... things like that, i would however strongly discourage doing so, simply because the 3 i assisted, came out deformed or hardly breathing and ended up by dying shortly thereafter, i know it sounds horrible to say, but if they can't get out of the egg, they are very likely to have something wrong with them, something that won't allow them to live regardless,
hatch rates can be as low as 40% and for a first hatch, you just need to get the hang of it, good luck though! i know this time was very stressful and scary for me, however i hope your experience ends up being just as worthful for you, as mine was for me!
btw, if you have any other questions and such feel free to pm me, as i've finally gotten used to the ropes of having baby chicks!