Start now or wait a few years? Purchasing Rental Homes

[Drake Turner]

A little Background: 

Currently 21 years old. Bought a foreclosure at 19 for $39k, remodeled for ~35k, just appraised at 100k (went a little overboard on the reno and it is overbuilt for current comps). 

We are in the process of refinancing for 15 years. Both of us are still in college, and working full time. $72k in total student debt $50k of student loans are sub-4%. 22k are 7%.

 (all still deffered), home mortgage will be 80k @3.5% ($600/mo). Current gross income 60k/year, will likely go up to 70k/year in the next 3 months. No credit card debt, no car payments, no other debt. Total expenses (including house) are roughly $2000/month. 

We have $20,000 in the bank. We want to get into real estate, looking mostly at buy&hold rental properties. We live in northwest Indiana about 30 minutes from Chicago. 

What is best? 

Should we look for a an investment property to buy now (likely a duplex, triplex, or quad), or spend the next few years paying down all of the debt? We will both graduate May 2018 and will likely have no problem getting a job which will lead to a rough doubling of household income(she is going for nursing and I am going for accounting). We really like real estate and enjoyed reno'ing our current home. The idea of trying to buy a rental property and deal with tenants and background checks and collecting rent is very intimidating and we do not want to mess up, but this is something both of us have always been adamant we want to do at some point. 

Any advice on what to do would be appreciated. Thank you guys!