21 years old - 20k - what to do?

[Ryan Koehler]

A little background: I'm a 21-year-old rising senior at Clemson University with about 20k to invest. I have my Pennsylvania Realtors License. Besides taking some real estate classes, my only experience in the field involves two real-estate internships and some personal tax lien investing background. 

If you were standing in my shoes today, what would you do in this situation? What REI strategy? Or, where would you go from here?

Thank you in advance and I really look forward to hearing everyone's thoughts.