Investing is not risk-free and investors seeking higher returns should be prepared to accept more risk. A higher risk level will typically experience bigger market ups and downs than a lower risk one, but over the long term (5 to 10+ years) a higher risk level should perform better.
If you need to access your money soon or feel that a portfolio that moves up and down a lot is not for you, then you may want to choose a lower risk level.
However, if you're investing for the long term and are comfortable with your investment balance moving up and down a lot, you may want to choose a higher risk level.