In addition, I'd say one of the most important choices a young adult has on their financial journey is whether or not to go to university and when. This, especially, in the United States where it's so easy to fall into years of student debt for nothing.
My biggest advice; have a clear motive for university and make sure it is advantageous to your plan.
I spent $40k on four years of university (luckily, I was working during those years and was able to graduate debt-free). To this day, six years later, I've still never spoken about my education with any potential client.
If I would have known I'd move straight into content writing after graduation, I don't think I would consider a degree as crucial to my success. Thus, I would have saved a lot of money I could've invested.