Someone once told me, “Just go out and run.”
If your main aim is to enjoy running, that’s a perfectly sensible strategy to take. If your main aim is to stay fit for life, you may want to include some other types of training.
Stretching, strength and mobility all play a part in our overall health and, “muscle and bone strengthening and balance activities [can] delay the natural decline in muscle mass and bone density that occurs from around 50 years of age, maintaining function in later life.”
So yes, if you want to run, just run, but perhaps think about the long-game, too.