first time investor multi family

[Caroline Berno]

I am a brand new investor and am pursuing a multifamily 4 unit in Lancaster close to the hospital.  B neighborhood. 2500 square feet. It is listed at 268,000.  Taxes are $4000. 3 out of the 4 units are tenant occupied lease running out in December.  Rents run as little as $750 a month and could go up for this neighborhood.  When I run the numbers it cash flows at $500 a month.  Since its my first deal I'm getting cold feet. Does this look like a good deal? Am I missing anything?