Why did no one tell me about investing in the stock market? Im having huge regrets

Im 29 years old, and up until 28 i never invested and just thought you are supposed to be frugal and stack up cash in the bank. It thought investing is similar to gambling and that you have to have alot of knowledge about it. I didnt know about the simplicity of investing in the S&P500 I still was able to stack up alot of money since i live in my parents house and now have it all invested through a lump sum but everyday i think about the bull market i missed in 2023-2025. I hate how online finan