I'm with you ol timer. I'm 62 and in pretty good shape and just chomping at the bits
First of all, if it were possible for ol codgers like us (and I am convinced that we who have military experience and knowledge, like mine in Military Intelligence could contribute to a substantial degree) I would first and foremost, join OUR military.
On the other hand, if I were younger, I might consider joining the IDF, providing the language barriers and citizenship obstacles could be overcome.