What's holding you back from just giving it a try?
Strength training at your age brings a LOT of benefits, no less than when you're younger. Your friends probably mean well, but they're off base here. Once you hit 50+, you're continuously losing muscle mass and bone density without training - that's scientifically proven. If you start now, you'll slow that down and even regain some strength. The people I know who started training at your age became noticeably more mobile and energetic after a few months. You don't need heavy weights, but consistent training with moderate weight is perfect for you.
Getting started is what matters most. Find a gym with good trainers who have experience working with older beginners - they'll show you proper form so you don't injure yourself. Start with basic exercises (squats, push-ups, rowing movements), two to three times a week, and don't get discouraged if it feels tough at first. After two or three weeks your body will adapt. The key thing: do it regularly, not sporadically like you might have done with walks before. Your health will thank you for it.