This post is incomplete.
Here is a procedure for making big decisions. It is motivated by some knowledge of what makes humans tick.
Set aside a full afternoon for this exercise. What you’re about to do is very important: it’s a life exercise, which will quite possibly shape your life. Devote time and attention to it. Make sure you have refreshments available throughout: water and some kind of sugary thing. Humans think differently when hungry.
This is your life decision. Other people may help, or may even try and influence you, but ultimately it’s your decision. “What others think” is a category we’ll come to later when you are considering the future. For now, know that you are the one doing the thinking.
There will be a lot of writing going on during your decision-session. Human brains are not great at holding lots of information in place at once and judging it as a whole, so you will use paper to hold your thoughts. That being the case, your paper will be an extension of your mind. Afford it the same privacy that your mind currently has. Commit now that you will never show this paper to anyone else. Anyone. Shred it afterwards if necessary. This will free you up to write down everything that is relevant, without fear of people discovering what you really think.
On that note, throughout this process you need to be the most honest you have ever been. There may well be things you would never dare admit to anyone (your best friends, your closest family, and so on). It is all too easy to fall into the trap of not daring to admit those things to yourself. But during this exercise, you are trying to discover the truth about what you should do in the future. You need to be totally honest; do not lie to yourself. No-one else will ever see what you write down now, so if you do lie, you really and truly are lying only to yourself. Any lies you tell yourself will interfere (perhaps catastrophically) with the process of finding the truth.
Maybe since the age of five you’ve told everyone you want to be a lawyer. Now you’re coming to decide whether to go to university, and what to study there if you do. Everyone knows you want to be a lawyer, and you’ve told yourself so often “I want to be a lawyer” that it just trots off your tongue. In this exercise, perhaps you come to write down “I want to be a lawyer”, and feel the slightest niggling doubt. Listen to that doubt. Try and work out where it’s coming from. If, deep down, you don’t really want to be a lawyer, it would be a disaster if you became one (law is, after all, notoriously boring). Years and years of tedious, difficult training, followed by years and years of tedious, difficult work.
“I want to be a lawyer” is here the kind of lie that you must avoid telling yourself in this exercise.
How to begin
You’ll be making lists. Lots and lots of lists.
Start out by writing the question, precisely, at the top of a sheet of paper. For instance, “Should I become a lawyer rather than a used-car salesperson?”, if you face a choice between becoming a lawyer or a used-car salesperson.