[William 辰]

Indigo's, Crystals, Rainbows and Starseeds are all different names for exactly the same kind of entity.
We are all from the same timeless place. So age is irrelevant.
Anyone who is in one of these "categories" is an experienced soul. The difference in the amount of experience between people is irrelevant. Because everyone is here to do their own thing. By doing so, you automatically help the world become a better place.

The different names come from that people have started to notice certain change of behavior from different groups of people. The names have changed because the qualities have changed. The qualities have changed because the previous generation succeeded in cleaning the world a bit more. Because the world is cleaner it is easier for higher consciousness to incarnate. And that continues without end anytime soon.
And old souls don't have to wait for a new body to raise their consciousness either. If you really want to, you can do that through intent.
All those "groups" are essentially the same.

So my advice would be: Forget all those names and definitions and just relax, have fun and do your thing.

Naming the next generation of old souls is a bit like naming a natural disaster. It doesn't add anything to the phenomenon, it's just easier for reference.