You are never too old to get younger
Krav Maga is a Close Quarter Combat (CQC) fighting system developed for the Israeli Defense Forces in the late 1940s by Imre Lichtenfeld. It is similar to Kung Fu San Soo in that it is very aggressive and anything goes. It is fast and it is brutal. It is not pretty. Notice that the practitioners do not consider it a martial art. One of the benefits of Krav Maga is that it is relatively easy to learn. There are no forms like there are in other martial arts or fighting systems. You learn to simultaneously attack and defend. You move in aggressively on the opponent, sometime pre-emptively, and you fight until the opponent is incapacitated. Krav Maga uses empty hand techniques as well as knife, gun, and other weapon defense.
Elements of Krav Maga are taught at the Albuquerque Taekwondo and Self Defense Club.