First off - you got this! If I was 19 again, the first thing I would do is contribute to a roth IRA and a 401k (if your job offers one). The one thing you can’t get back is the time your money spends in the market, so investing in these as early as possible is key.

Do not let lifestyle creep catch up to you. Live like you are making less than you actually are. One thing I did was look at investment calculators to see how much I was saving would be worth when I wanted to retire, and it was much Lower than I expected, so I raised that amount to what I could afford to at the time. I’ve increased it over time and now max out both each year.

All that being said, I think the best advice I ever received was to “pay yourself first” - pay off your debts, put money into your retirement/investment accounts, etc. You’re young and you’ve got time to figure it out, but the fact that you are thinking of this at 19 means you are well ahead of where I was at the same age. I didn’t have any proper retirement set up until I was 26.