I have plenty of weak memories. I know in high school I was curling dumbells that must have been 3.5kg or something. At basic training I couldn't do a single pullup (though I'm not much better than this now but working on it). I also have in my log when I was squatting 20kg and had to lift the bar over my head to do it because I had no rack.
Keeping a log is the best bit though, it shows where I started and where I got to after consistent training, motivating me to get back there.