So, this is the result of a multi-person rant about the ridiculousness of the Jedi in particular, but it ended up going somewhere kind of unexpected? Anyway, enjoy, and I do not own any part of the Star Wars Franchise.
You join the Sith Order at sixteen.
You spend three years being taught discipline and emotional control. The Sith must know themselves, for if they do not control their emotions, their emotions and desires will control them. The Sith are the soldiers of the Republic, they fight what battles need to be fought and command troops, they assist the officers of the law in aprehending dangerous criminals and taking down drug lords and their ilk. If a Force Sensitive cannot learn control, they cannot be allowed to become Sith, because a Force Sensitive who drowns in the Dark Side becomes a beast, which the other Sith must hunt down.
You do it, though. At nineteen you are promoted to Squire, apprenticed under a full Knight to learn the the practical demands of the job. Your Knight Master, Ku-han, is strict but fair, and you learn much from him, joining him in his missions starting in the second year of your apprenticeship. You take to the work with ease, fitting without trouble into the dark places of the galaxy, as a dark thing yourself. At his side you capture dozens of criminals, you take down a slaving ring operating secretly in the Middle Rim - you even assist him in a battle against a Fallen Sith.
It is after that battle that you are brought before the Council of Nine. They Knight you with all ceremony, praising you for you excellent grasp of combat force techniques in particular. Your former Master lays a proud hand on your shoulder as you are gifted with the badge of your station: a kyber crystal of vibrant red.
You serve the Sith Order for thirteen years. In that time the Republic becomes aware of a growing darkness in the Outer Rim; slavery has grown rampant there, some sectors treating the practise as though it is entirely legal. The Sith are ordered to take care of it, and they pull out all the stops. All Force Adepts believe that freedom is the right of all sentients. The slaving operations in the Outer Rim are decimated by the time you are thirty. Some remain, and more will replace some of the others, for evil can never be truly erased from the galaxy, but for the most part the practise has been excised from Republic space.
When you're thirty-six you start slowing down. Despite Kuwan and Jedi healing abilities, old injuries begin to catch up to you, and you simply are no longer the force on the battlefield you used to be. While some Knights remain with the order past their field days, learning the secrets of the Dark Side and joining the ranks of the Sith Masters, you feel that you can do more among another Order. You're not alone in your decision, and the process of tranferring to the Kuwan Order is quick and painless.
You begin your time among the Kuwan learning under a Master Agriculturist. On the side, you take classes in diplomacy, in psychology and languages, supplementing your less comprehensive training in those areas among the Sith. The skills necessary to the Kuwan are different than those most useful for your old Order. Here you learn to tame your wild edges, learn to smooth the path away from conflict. You learn how to read a person's mood, how to word your statements to appeal to the better nature of those around you. You learn how to weave the Force around a seed and make it bloom.
When you have passed all your classes and received commendations from your Kuwan Master, you are awarded the rank of Adept. They send you to starving worlds, where you make crops bloom and teach the people to farm sustainably. You negotiate treaties between Republic citizens who might otherwise come to blows (sometimes you jokingly apologize to your former bretheren for depriving them of fun, usually when the citizens in question seem like likely targets for Sith operations). Once in a while you get dropped into situations where you are forced to defend yourself, but your scars do not yet bother you so much that you cannot wipe the floor with a few idiots.
You work with the Kuwan Order for thirty-three years. You learn much, from your Kuwan brothers and sisters, from Sith bodyguards on particularly dangerous missions, from Jedi advisers who join you sometimes for negotiations. You settle conflicts and save millions on ravaged worlds from one end of the galaxy to the other, tending to the safety and prosperity of the Republic you serve. You are satisfied with your contributions here, and you have become tired of spending your life in transit more often than not. At seventy years of age, while you could have chosen to remain, becoming a Kuwan Master, you choose to join the Jedi.
Among the Jedi you find yourself something of a novice once more. While filled with real experience in the world outside the peaceful order's walls, you have spent your life in the center of the action, fighting the good fight. The Jedi are scholars and philosophers, healers and ocassionally eccentrics. You still have much to learn.
You spend much of your twilight years among the holocrons and datapads, learning the workings of the world and the secrets of the Force. For the first ten years, you sometimes choose to join younger Kuwan Negotiators as an adviser on those topics you find particularly interesting, but as you age you take these missions less and less. You spend two years as one of the three Jedi who sit on the Council of Nine, assisting your sibling Jedi and your wilder cousins in administrating the Three Orders. You meditate, pondering on the deep questions, exploring your connection to the Force. You find peace in yourself, satisfied with all the good you have done.
One night, when you are ninety-four, you fall deeper within meditation than you ever have before. In one sense, you don't return. In another, you never leave; as you have always known, the Force is everywhere, and you are the Force.