Progressing in spiritual matters is less a matter of years but more a matter of growth. There are relatively young souls who progress rapidly, as by their nature they learn rapidly and do not hesitate to apply their knowledge. And in between are the vast majority, who linger at points, revisit areas they have passed through before to solidify lessons, and become blocked due to their natures now and then.
A soul is unaware of its status, but tends to recognize other strong souls during an incarnation. Old souls almost instantly recognize each other. This is not a body language issue, as the human can be unaware of the age of their soul, other than that they find they are focusing on issues differently than others around them.
An old soul often finds they are strongly at issue in good vs evil agendas, or take action suddenly to situations where others about them are debating and unsure. An old soul often has a skill set that surprises the parents, expressing early in the life of the young human whose knowledge and skill are coming from a source other than the education being given by the parents.
Thus, there are clues, but the old soul in a young body feels, most often, strange and apart until meeting others of his kind.
At what point do incarnations cease to be a learning tool? Humans entranced with Out-of-Body experiences imagine this to be a goal, as they see so many advantages. They could spy on their neighbors, gain information useful in power plays, and just travel without expense or distress. However, soul intent on their lessons do not consider such skipping out of school an advantage.
1) Incarnations trap the developing soul in a body with limitations
2) Incarnations create the need to be creative, and resourceful
3) Incarnations put the developing soul in pain and distress, frustration, longing, so that the soul has empathy later for others in this situation
Thus, incarnations are seen as a type of tool, and until the soul has grown beyond this point, and has learned all the lesson that could be learned from incarnations, there is no press to avoid them. Humans experience Out-of-Body during suffering, as many Near Death Experiencers will tell you that they viewed their moment of death from outside their body.
Torture, or intense pain, will likewise cause the soul to jump out of the body, and the body and soul then remember this and attempt to repeat it. This is discouraged by the Spirit Guides, who consider this skipping out of school, and the soul is forced back into the body by various means.
We must always listen to the Spirit Guides...they are ever present, even if we do NOT see them, or they choose NOT to make themselves known. Remember, we are watched over for the children that we really are.