A few things to consider here that have nothing to do with exercise or diet:

• Aging trajectory. Remember when everyone was at a completely different point in physical development back in school?^1^ It turns out that everyone’s body-clock for biological aging is just different, and folks hit different milestones at different points.
• Resilience. We get less physically resilient when we age. IMO, it’s inflammation related. Again, everyone has a different timeline for how fast or slow this happens.
• Sports (in the past). Some people tore up their bodies playing high-impact sports. Those injuries come due later on, usually in the form of joint problems. At the same time, being sedentary can exacerbate that condition - they made choices as a teenager that obligates them to keep exercising or going to PT.
• Circadian rhythms. Some people have lifestyles that do not line up with their body’s need for sleep and wakefulness at all. This results in a sensation of being permanently jet-lagged, because they are.
• Stress. Whether it’s psychological or physiological, it all adds up and does wonders for complicating all of the above.
• Entitlement. IMO, it’s a natural inclination to feel entitled to a comfy, pain-free existence when you feel that you’ve done everything right so far. That said, your body may decide to have other ideas one day, and leaves one feeling kind of betrayed by forces beyond their control. Not everyone is equipped to handle “it is what it is” and just accept it out of hand. It’s a recipe for complaint and, honestly, requires psychological support to overcome.

So you may be (naturally) making better life choices in these areas that fit with your particular biology, and/or you have really good genetics at this stage in the game.

^1^ - We all knew that one guy that was rocking an adult body at 13, in the same class as some kid that was still waiting for puberty to hit. Shit was wild.