Life expectancy of person with pacemaker due to heart block?

My GF was born with heart block and had to have a permanent pacemaker put in her. She says she can live a normal life etc.. Other people say she will probably die before she is 50 and will be sickly until that point.. Anyways, it hurts me to hear that.. Can she still have a normal life? Can she have kids? Will heart block and pace maker lower her life expectancy?