Should I invest in growth stocks or blue-chip stocks when in the early 20s?

I think you have a bit of misconception here. A growth stock can also be a bluechip stock (eg Mastercard.) What you probably mean is either a growth stock or a dividend stock. As a young adult, it is better to tilt more towards growth, but its important to own some dividend stocks too.

And a better plan for you instead of RSP into individual stocks, you should just buy a Growth based ETF like QQQ instead. With $200-$500, it is a really small amount if you are buying individual stocks... hence you are better off buying ETFs/Robos since the capital injected is small.