A stock market tumble doesn't worry one young investor who is taking to heart the advantage of compound interest: the earlier you start investing the more money you can potentially make.

He took it so seriously that he bought his first stock at age 12. And now he's sharing his knowledge.

Last month, Daniel Scrugham launched his free investment podcast called Early Investing. But he has been doing real investing for years.

"When you invest early that will exponentially grow your returns over time," he said.

He saved up money from birthdays and Christmas.

"After maybe a year or two a year and a half of research in 2015 when I was 12 years old and turning 13 I bought a share of Google which later became Alphabet," he said.

He bought that one share at $540.

"I have more than doubled my money," he said.

The15-year-old admires the investors Warren Buffett, David Gardner who started the Motley Fool, and Peter Lynch.

"He said buy what you know. He said if you want to be an investor, this is great advice, just look around your house. What brands do you use?"

That's why Daniel bought Google and Under Armour and Shopify and more.

"Recently I had to sell several of my stocks to buy cryptocurrencies because I found some cryptocurrencies that I liked even more than my stocks. Those are the three reasons I sell: when you have a better place to put your money, you need the money now, or when the original vision for the company no longer exists," he said.

Daniel is starting his own company as part of the Young Entrepreneurs Academy. At the end of the academic year the students in the program will face a panel to try to get funding.

The Early Investing Podcast is part of his business. His target audience is students.

"I know you have to make a custodian account and you have to do this because you're not 18 yet or you have to do this because you don't have all this money so I can give people the perspective of someone their age," he said.

He is working on a way to make money from podcast advertising or an investment newsletter subscription.

Meanwhile, his money-making strategy is to buy stock in companies he believes in without paying much attention to the price.

"You don't buy stocks, you buy companies. And you just hold your companies over the long run. And the companies will produce great returns," he said.

Daniel says he will address the stock market drop in this week's podcast. But for now he is following Warren Buffett's advice to be "fearful when others are greedy and greedy when others are fearful" and to buy and hold good deals.