You're never too old to learn how to play chess.
What I would recommend is playing regular games and analyzing them (as you are already doing), doing some tactics puzzles (on chess.com or chesstempo), and study openings regularly. That's what I've been doing for the past 2 or so months and my rating has improved from 900 to the high 1200s now.
I started playing chess nine months ago. I practice constantly. I work on tactics, openings, pattern recognition etc. and I play a lot of games against the computer and other players. My rating is between 1100-1150. I use the chess app "analyze this" to go over my games. The tactical mistakes that I discover I make seem astounding to me after the fact. Is it usually the case that players that have been playing for almost a year to keep making fundamental errors during a game? I am worried that I may not have the knack to ever be able to play in amature tournaments. I am also 54 years old. A bit old to learn to play chess?