Hey c172g - running's great and I hope you don't get any problems. I've been been running for over 20 years now but I'm now 40 and have had a few niggles in the last few years. I guess we're all built differently so some of us would be more prone to injuries than others. I used to run with some older friends (ultra marathon types who would tire me out after 15 km and keep going the same pace for another 35 just for fun!) but when they hit their mid-40s they started having problems eventually needing surgery. Don't want to end up like that if I can avoid it
On my Saturday run I often see a guy shuffling along who'd have to be around 80. Always smiles and says 'Hi'. That's one of my goals - 80 and still running!