Becoming a successful entrepreneur can happen at any stage of life. Some entrepreneurs become successful after years in the workforce, while others start a company as their first job ever. While a majority of successful entrepreneurs actually start companies later in life after gaining real-world experience, a lot can be learned from those who became successful entrepreneurs before reaching the age of 30. Below are seven of the most successful entrepreneurs who became successful in their 20s:

Mark Zuckerberg started the social networking site Facebook (NASDAQ: FB) and became a billionaire at the age of 25. Zuckerberg started the company in his dorm room at Harvard and is a self-taught computer programmer.

While Matt Mullenweg might not be a household name, his work is definitely well-known. Mullenweg led the open project that later became known as WordPress, which powers more than 20% of the websites on the Internet. Mullenweg's net worth reached $40 million by the age of 25. As of July 2015, Mullenweg is the CEO of the company Automatic, which is valued at over $1 billion.

David Karp is the brains behind the website Tumblr, which he created while working as a software consultant. Tumblr is a blogging platform purchased by Yahoo (NASDAQ: YAHOO) at the direction of Marissa Mayer. Karp is currently the CEO of Tumblr which he is operating as a subsidiary of Yahoo.

Karp's net worth reached $22 million before he turned 23. He found initial success when he raised $5.25 million from seed investors, two of whom were instrumental in the success of Twitter (NYSE: TWTR). Both of these investors helped Karp take Tumblr to the next level, which allowed it to become an attractive acquisition for Yahoo.

While there have been many web browsers to rise and fall over the past 20 years, one has been able to remain a stalwart in the marketplace: Mozilla Firefox. Mozilla Firefox had over 100 million downloads in its first year on the market. While this type of success seems to be the product of an experienced entrepreneur, it was in fact Blake Ross who coded and launched the web browser. At 24, Ross reached a net worth of $120 million and has continued to take market share as Mozilla's user base grows.

Sergey Brin is one of the two brains behind Google (NASDAQ: GOOG). The company was started when Sergey, 25 at the time, and his partner were doctoral students in computer science at Stanford. Wanting to find a better way to search the Internet, which in 1996 was highly fragmented and hard to cull through, Brin decided to build a search engine that ranked search results by the number of backlinks rather than the amount of times the search term appeared on the page.

This approach to search allowed the best content to rise to the top, given the fact that at the time, a backlink signified the website had content good enough to be shared by other websites. Since then, Brin and the Google team have strengthened the search algorithm to deliver even better search results.

The other half of the founding Google team is Larry Page, who like Brin, started the company when he was 25. His success story is much the same as Brin. As a 25-year-old doctoral student, Page helped Brin change the way searches are conducted on the Internet.

It is fitting to end this list of entrepreneurs who became successful in their 20s by highlighting one of the most famous entrepreneurs of all: Steve Jobs. Although people think of Steve in his later years, he actually started Apple (NASDAQ: AAPL) with Steve Wozniak when he was only 21. Since then, Apple has grown to become one of the largest companies by market cap in the history of the world.