No. A general confession is not necessarily of the sins of an entire lifetime. A general confession is a confession that covers a certain period of time, normally broader than an individual confession, up to an entire life in some cases. Why would one do such a thing? Because at times there are periods that we realize we need to consider, and offer up sorrow for, as a whole, because we come to discern patterns. The point is not to deny God’s forgiveness, but to deepen our own contrition and abandonment to divine providence, and open ourselves up to direction with respect to the general motion in our lives, which is why these are appropriate before major changes of life (marriage, for instance). Of course, they can also be made if we are aware that we have offered bad confessions earlier, but that is another case and should happen very infrequently if at all (the danger of scruples is always there).