Please Google "Compound Interest". Once you really understand how CI works, you'll have your answer.
From US News, with slight modifications, to whet your interest:
"Obviously, if you just put $1,000 in an account yielding 2 percent and let it sit for years, your money wouldn't grow very fast. The key is to continue adding money to your savings[/investment] account regularly so that you have more money to earn interest. The magic of compound interest is that the more you put in, the faster your money grows.
Compound interest is also more beneficial the longer you have your money in a savings [/investment] account, so the earlier you start saving, the better off you are. You can use a compound interest calculator to help you make projections.
If you are 25, and you start with $5,000 in a savings [/investment] account, and you put in $200 a month for 40 years, your money can grow to $158,904.25 by the time you are 65. If you can up your contribution to $500 a month, you can end up with $380,700.34. If you start five years later, at 30, you only end up with $315,965.65. You miss out on tens of thousands of dollars, just by getting a late start."
This one should really blow your hair back:
http://www.businessinsider.com/amazing-power-of-compound-interest-2014-7