Which word indicates a beginner or a young person ready to leave home?

The word "fledgling" is an apt choice as it specifically refers to a young bird that has just acquired its feathers and is learning to fly, symbolizing a novice or beginner in a broader sense. In a figurative context, it captures the essence of someone who is inexperienced or still developing and can also imply a readiness to embark on new experiences or leave the safety of home, akin to a young adult stepping into independence. This aligns perfectly with the idea of a young person poised to move into new, uncharted territories of life.

On the other hand, "expert" signifies a high level of proficiency or skill, which does not relate to a beginner. "Veteran" refers to someone with considerable experience, often in a particular field or context, thus again differing from the concept of a young individual ready to begin their journey. Lastly, "matured" implies a state of having grown or developed fully, which contrasts with the idea of being at the early stages of life or experience.