I'm 44. Soon to be 45. Been weight training since I was 15 (1985). I am still gaining strength.
The physical attributes lost at an early age (lateral foot speed, etc.) are NOT important in the pursuit of absolute strength. Hence why strength athletes very often "peak" at relatively advanced ages (40s-50s). If one does not use/abuse anabolic drugs, and therefore ruin his his hormone system and joints, etc., to develop crazy strength well in the middle-age period is very doable.
Most popular sports (baseball, football, basketball, gymnastics, etc.) rely on those attributes that are at their greatest when young.
HTH
A few years younger than me, but similar progression in strength. I'm stronger, or as strong as I ever was.