He said, "Bitcoin investment seems to be late, to be honest. I'm sad, too. I think 2018 was the last chance for ordinary people."
Too late I don't think so..afaik people can still invest as potential to go to $100K or $500K still exists, but if he referred to owning a whole bitcoin it could be the case as price as gone up for everyone of us to own atleast 1BTC.
I'm so pathetic and depressed because I didn't know Bitcoin quickly. What should I do?

You don't have to stretch yourself by buying a whole Bitcoin, slow but steady wins the race and you can invest in BTC the DCA way...
There is no price we buy Bitcoin that we are not going to make profits from the market even if we bought when the price of Bitcoin was $60k. The mist important thing is patient for us to hold and wait for when the price of Bitcoin will come back to that same price and keep going so we can take our profits. Bitcoin is a volatile projects so we need to buy low so that we can sell high. The difference from the price we bought and the price we sold is what is going to determine our profits whether we are won or lose. If the price range is high, that means we are going to make a lots of profits if we have large holdings too.