I read just last week that one thing that contributes heavily to aging both in terms of appearance and physical health is poor posture. Rather it be forward head, rounding of the shoulders, thoracic kyphosis in varying degrees, or hinging at the hips, any one of them can make you appear older than you are. Any one of them can make you feel older than you are. While I am tempted to write on each of those issues, let me instead offer a couple of suggestions that may help improve posture even if it is a temporary fix.
#1. Stand in a relaxed position in front of a mirror. Let your arms fall to the sides of your body with palms facing inward and the thumbs facing forward. As you look in the mirror, pull the arms in close enough so there is no space or light between the arm and the side of the body. Don't skip this step! Without moving your upper arm, turn your hands so that your thumbs face the side walls or even the wall in back of you. You will feel your shoulder blades move toward your spine and down. Your posture improves.
#2. Again standing in front of the mirror, lift the chest. The shoulder blades slide down and back. Posture improves.
These are easy tips to help you stand up straight, right? I know Mother always told you to stand up straight. That was supposed to do the trick, but when the muscles are weak, the body finds a way to compensate. The best solution is still to get into the gym and push and pull for a stronger back.