Thoughts on this Roth IRA strategy?

I just turned 21 and I opened a Roth IRA in February.

Currently, I'm invested 80/20, S&P/International.

I've been doing a lot of research and reading about investing in Roth IRA's in general and I'm now debating if I want to start contributing to make my split 70/15/15, S&P/International/Large cap growth.

Is there anything I should add? I feel like I'm to young to worry about bonds but would it be smart to have a small percentage now? Or investing in single companies, Apple, Amazon, Google, Coca Cola.

I'm open to anyone's thoughts or personal experiences.