Your 20s are a time for figuring things out. For leaving your purse in Charing Cross McDonald's at 3am, forgetting to cancel your card then, when someone buys 10 Big Macs with it, just taking the financial hit because you’re too hungover and ultimately, can’t be bothered calling the police. Just an example off the top of my head.
It’s also a time for making mistakes, and learning from them. So let me speed up that process for you, by sharing the money-based lessons I've learned over the last decade.
I went into my 20s very much checking my bank balance once a year; now, on the eve of my 30th birthday, I have an app on my phone that helps me invest money for my future. I also don’t go to McDonald's at 3am anymore. Part of me is devastated by this (I’m old), and the other part is euphorically smug.