Two-fold problem with your logic here Nothing you do today has to be done for 40 years and most of your angst and self stone walling is coming from anxiety about a future you cannot know/which doesn't exist. Try to learn not to mix your imagination with your logic, anyone who thought all they were going to do is sign papers for 40 years would turn away.

Make a year-long, logical plan. Buy an artist's notebook and get "a" job. Journal about the job, both in words and drawings as you explore it. Does not matter what the job is, use your imagination to make it "your" job for that year. If you get a job as a dish washer, come up with a system that is better than how they train you to do it. Sketch/draw/paint, etc. the beauty of those soap bubbles. Learn to get along with a "rough" crowd that has been raised wholly differently than you have and has a different background, has had different experiences, is seemingly "stuck" because of that background and education. What would you do if you were in their shoes? How would you work your way out of it?

That is how to use your imagination, not to stop yourself by taking on the entire make-believe world of the future you imagine (where you single-handedly support your entire family :-) but to create yourself as you go along, to discover what your life and experiences will be as you live them, subtly influencing them by choosing what you like best, what you want, moment to moment.

Just like we are supposed to imagine ourselves as all characters in our night dreams, since they are our dreams we have created and we have created "that" character for a reason only knowable to ourselves; imagine your daily experiences the same way. Don't just be the dish washer, be the waitress putting up with the rude customer, be the customer, be the short order cook, be the owner, be Zorba Find which role in front of you suits your character and interests.

Do all this in relation to the logical 1 year plan Save X euros for Y purpose, give your family X euros for your room and board, join a group where you meet others in a similar situation to yourself in some way or similar interests and plan the next step. Study the science of dish soap, the mechanics of kitchen appliances, scribble about your hopes and dreams in your journal, paint what you know (the beauty of sex) and interview with gallery owners and graduate schools; aeronautical, dish soap, kitchen appliance companies...