I had no idea what I was doing once I finished school.. just worked for the family business for a while then moved states, went to Uni but got bored so worked various jobs from basic support to management roles... eventually moved back to my home state and went into the mining and construction sector which i did for a fair while and enjoyed it plus the pay is excellent here in Aus.. eventually tried uni again and got bored again so stuck with the former work.
Eventually in my super late 30s I took the plunge with the support of my wife to change careers to one that I had wanted to pursue for a very long time. It pays significantly less (pretty much halved my pay) but the job satisfaction and work/life balance is fantastic.
Could I have done things better in my former years? Absolutely, I squandered my large income (although we are most certainly still living comfortably) but I wouldn't change it as it's given me an amazing wife, 2 brilliant kids and a lot of fun memories and led me to a job I love.
Follow your own path, try new things and take it all as a learning process. Some people have things figured out from day 1 others like me take 40 years