I (25M) definitely know what you mean. My experience is probably going to differ from yours because I work as a social education worker and not in a business field – I imagine the hiring process differs quite a bit. I definitely have been turned down because of my stutter but I think it's important to not let those experiences discourage you. If they get hung up on your stutter and don't see your qualities beyond that, I think it wouldn't have been a good fit anyways. Your stutter is part of you, but it doesn't define you or your qualities.