it's very depressing because I think it's too late to invest in a great invention that comes out maybe once in a thousand years.
Don't get depressed. Many of us here have heard Bitcoin earlier than you but did we give up? No. We also thought the same thing as you but it was never too late for anyone to invest. Are you thinking that your $100 might not be enough? Because it isn't enough if you're going to take a look at the market price and it's unlikely that we're going to see it that low because of the movement that it has got from few years ago and with halvings and many adoptions that happened, you have to consider its growth.
Their is no late time time for you to invest in bitcoin, even at the price which bitcoin is currently is , it is not a bad idea to buy bitcoin because we are entering the bull market, but wellif one feels and doesn't have the mind or understanding to buy now they shouldn't force themselves to invest because even if they dont have the believe that it is right to buy now just because of bitcoin price has increased to this current price they may still not have the patience to hodl to the investment.
I noticed that now on the forum opinions are very much divided on the issue of "is it too late to invest now or not?". Personally, I am absolutely sure that now it is not worth changing your cache and fiat (or stable coins like usdt) to bitcoin. The fact is that now the price has hit a powerful support level of 45k, which appeared on February 7, 2022. I understand that the price has overcome it, but has never been fixed above this level. I think now Bitcoin will fall in price to 36k.