TL;DR: Being a beginner at something is great, especially if it’s something that humans are built for.
Humans are, among other things, persistence hunters. That means one of the ways we are adapted to catch prey is by the brutest of brute-force techniques: on foot, we follow a large animal as it runs, until it sits down and dies of exhaustion, whereupon we eat it. We’re pretty slow, but we can run for hours in the full heat of the day (we’re unreasonably effective at regulating our own body temperature) and we just don’t stop. One of the adaptations by which the human body is built is the ability to run at a constant speed for a long time. This art is, of course, increasingly unnecessary, as we have supplanted it with tools wrought of pure intellect (agriculture and so forth); but the underlying mechanisms are still there in [most of] our bodies.
If you start something as a beginner, you make extremely rapid progress. The general effect has a name: the Pareto principle, which is a rule of thumb which states that 80% of the effects come from 20% of the causes. If you just learn the most basic 20% of something, that often gets you 80% of the total possible effects. Beginners improve rapidly in most human endeavours.
I started running using the NHS Couch to 5k programme, about nine weeks ago. In that time, I have gone from being able to run fitfully for about thirty seconds before having to stop and breathe, to being able to run for thirty minutes and only stopping because that’s when the timer finished. It wasn’t particularly fun, but it’s always satisfying to improve rapidly at something, and it is certainly better to be able to run for half an hour than not to be able to run at all. (I had a similar experience with lifting weights, a year and a half ago, except I actually find that fun.)
This post is to recommend being a beginner every so often, and specifically to point to the Couch to 5k programme for those who don’t currently do things that involve running.