The where, what and how of investing in your early 20s: What you need to know to start investing.

Your 20s are a pivotal time. There's no longer any question that you're an adult. You even clean your own bathroom – or exercise your right not to – to prove it. As an adult, the decisions you face are a lot bigger than those of a teen, especially where money is concerned.

Financial decisions for teenagers revolve around how to spend their money: To buy the shoes or not to buy the shoes, that is the only question. As a 20-something, the questions you face are far more complex, like how to invest in your early 20s.

Your 20s are the the best age to begin investing because you have so much time on your side, says Shannah Compton Game, an Los Angeles-based certified financial planner and host of the "Millennial Money Podcast." "You can really build a massive nest egg for yourself," and you don't have to be an expert to do it.