Think very hard before enrolling in a 4 year (?!) diploma course at age 20... you will likely end up twice as lost at the end as when you start :) My recommend

Think very hard before enrolling in a 4 year (?!) diploma course at age 20... you will likely end up twice as lost at the end as when you start :) My recommendation is spend those four years working in as many different fields as you can get your foot in the door. Just try a dozen things in two years. Guarantee you will have a much broader view of what is possible than holding a diploma. Plus, you'll get paid for doing it. PLUS, you'll meet (and build relationships) with a lot more people. Particularly if you aren't good at just striking up a friendship, working alongside people is a great way to get to know them. Your milage may vary.