One thing I would add is that financial stability depends a lot on where you live and that is something you should be open to change if you are 23 years old. If you are in a country/ jurisdiction with great public services then you may be well off without having millions of dollars in the bank and would just be living an enjoyable life in a safe setting. The desperation for the millions comes from a history of instability and insecurity. We have all been there or have heard of stories about someone close being in that situation. When having money would really have made a lot of difference for them.
This becomes less important if you are in a great society and have a close bunch of people who will look out for you as well as you look out for them. Thus, on top of financial stability, I think everybody should give thought to deciding a place they think would match their aspirations and desires and then try to own property, preferably land there.
For me, being financially stable is when you are already financially independent - no more debt, can survive a daily basis without the need to work for it, and has a secured amount for the future.
Personally, I don't want to spend most of my life working in a company I don't own. I want to achieve financial stability with help of my skills, ability, and strategy. I know it won't be an easy task though. Surely, this would take a lot of effort, time, and resources to achieve, but definitely, it won't be impossible. Nowadays, it's really hard to earn money, hence we should not be complacent about our current earning status. It's not bad to look for additional side hustles that could generate you more income as long as you can still balance your time and give quality works to each of your hustles. We need to prioritize needs over wants. This is one of the keys to being financially stable - self-discipline. We must learn to restrain ourselves from buying the things that we don't really need, and instead allocate the money to our savings or investment so it could profit as time passes by.
Being financially stable for me also means securing my retirement fund. I want to fulfill it as early as possible so that I won't be thinking about it later when I have a family of my own. I want to have it to secure my future and to not rely on my children for money when the time comes that I'm of old age, I can still buy and do what I want.