People in their 20s can think they are not financially stable enough to start investing.  They may have student debt, low salaries, or just don't know how to start.  The advantages to start young are significant though.

Key takeaways:

Time gives you the power of compounding You can take more risk with years of earning ahead of you Take advantage of tech savvy resources for investing and learn from your successes and failures Invest in yourself by learning advanced skills that can earn you more money