I still think this article,
Becoming a Civilian Defender by @
Sherman A. House DDS, is the best place for most to start.
He suggests his list be accomplished in order:
WRT 1, Criminology/Street Smarts/Physical Preparedness: Subscribe / follow Aprill Risk Consulting (on Facebook or Intstagram) and the Active Self Protection main channel (on Facebook or YouTube). Skim through Dr Aprill's short news clippings and his comments and watch John Correia's short videos. It's a low barrier to entry that doesn't jam "Gun-Life" down your throat. Do this for a couple weeks or months. I bet you start to see some trends and can start determining your level of participation.
I would also add: improve general health. For most Americans, obesity and heart disease are far more likely to kill or "cause grave bodily harm" than a bad guy. Get to a healthy weight (BMI isn't perfect but is probably a good starting point for most) and do some modest cardio. Larry Lindenman's LSD workout program is a good place to start. This 1h20m podcast,
SSA: Fighting for Fitness with Larry Lindenman, gives some good, realistic fitness recommendations.