How important is the home defense part of the equation? If it is not really high up (don't live in a high crime area) then you might consider a .22 rimfire. That was my first gun, a Marlin 60. I still have it and I am in my late 40's. The Ruger 10/22 is also a good choice, lots of after market stuff for them is available (they are like the small block Chevy of guns). A .22 rifle, while not ideal, can be used for home defense but a shotgun would be a better choice. The .22 also has the big advantage of having cheap ammo.