The Amount of Deliberate Practice Is More Important Than Total Time of Experience

It doesn't matter how late you start learning something, because it usually takes a few years years to get above average, and most people never get past average. Even if someone has had a head start of many more years, you can get close to their level in a shorter amount of time since diminishing returns means that they would not be significantly better even if they had much more time.

In addition, the length of time of experience does not necessarily correlate with time spent on deliberate practice. It's possible for someone to have spent a lot of time doing a skill but not actually be far along the learning curve. Progress comes from deliberate practice.