Working out is important, but you also have to work with reality. At the age of 61, the arthritis in my hands will no longer permit me to bench press a barbell. Since I've been bench pressing for fifty years, I think I'm ready for a change. So I've switched to pushups. They hurt, but I can do them. At the age of fifteen, I could do about 120. To see if that's still possible, I intend to add one per week.
That has always been the way I dealt with pullups, my favorite exercise. At one time I could do eight reps with seventy-five pounds. Those days are over, but I still can do ten with forty-five. And my hands don't feel like they're going to explode. If you can do a good clean pullup, then eventually you can do ten. One way to increase your pullup strength is to stand on a bench beneath the bar and let your legs help raise and lower you. Another way is to use the bench to help get your chin over the bar, hold the position, then lower your full weight slowly. Don't give up. Add one rep each week, and you'll be at ten in ten weeks. Well, maybe eight, but that's still okay. Twenty pullups is not an unreasonable goal for a few months' effort.
A few years ago I tried this approach and got up to sets of thirty. Then I got bored and went on to something else. If you want to work out for a lifetime, boredom has to be confronted and beaten. Especially if, like me, you work out alone.