At this age, building muscle to look and feel better relies on quality (vs qty).
Do this when you weight lift:
1- pause for half a second at the end range of motion; no more bouncing in and out of reps; the pause, then powering out of the end range encourages more muscle fiber recruitment and power
2- aim for 10- 20 reps where intensity means you are having to struggle through the burn through the last 2 reps while still maintaining good form