As a new landlord, this will present the least amount of risk while your roommates/tenants pay down your existing mortgage.

Think of your roommate as an employee.  

Provided you've shown steady work and have saved up a decent amount of money, hopefully you can buy a place rather than rent and have roommates to subsidize the cost.

Get some room mates and a couple of 4 units with 5% down owner occ loans. and you'll be pulling in 17k a year in no time in extra income.

I pulled in out recently when I needed to draft a roommate agreement to protect the LL's (mine) interests. 

Call section 8 and let them know she has a unauthorized roommate, let tenant know your calling.. 

They bought a rather large house (5 bedrooms), and were able to have the mortgage covered by their 7 roommates, and today they are earning equity in an asset that has appreciated quite a bit as well.  

My roommate has been talking to me about real estate investing for the past few months and I've finally decided to jump on board! 

My area that I live in has really high prices right now, so even with a roommate renting out a room, it still would put me right on the line for what I would be comfortable paying monthly, and beyond what I would pay without a roommate.

I'm 25 and closed on my first about 5 months ago, and also rent to roommates.