There are things you can do now to increase your chances of running into your 70's.
Don't run consistent 70-90 mile weeks. (Maybe higher mileage for a month or so during marathon training) When I was in my 30's & 40's I only ran 40-50 miles a week. All my friends who were running 70 or more miles a week are no longer running.
Run on dirt or grass as much as possible.
Don't become a slave to your running diary. Don't run through injuries.
When I hit my mid 50's I cut down to 4 days running a week averaging 30-40 miles a week. (Unless I was training for a marathon) I usually ran a 3-5 mile tempo run (hard pace) once a week. I started doing more strides in my 60's. I'd only race 6-8 times a year. In my 30's I was racing 20-25 times a year.
An 8 minute mile at 69 years old feels the same as a 5 minute mile did when I was in my 30's. The only difference is the time on the watch.
I've never been flexible. Never able to touch my toes, so there's no change there.
Energy level is not what it used to be. Takes longer to recover from injuries.
I'm still running 25-30 miles a week (69 years old) but have slowed down considerably. An easy pace is now 10-11 minute miles.
My weight is the same now as when I was 35.
I have a terrible diet. I can't eat fruits or vegetables and am addicted to sugar, especially chocolate.