Questions about first House Hack

[Knoell Palmer]

Hey Bigger Pockets community! 

Excited to say that my girlfriend and I are finally taking a step into the real estate world! We've been doing a lot of research over the past few years and are currently looking at multifamilies in our area. We have found one that we are considering making an offer on but still have a few concerns before we pull the trigger. We used our best judgement in analyzing the property and come up with a barely negative cash flow ( around -$150) but feel like there's still a few pieces missing in terms of getting a positive cash flow. Part of the issue is that we've guestimated on some of the metrics used in analyzing the property ( PMI,taxes,mortgage insurance, etc.). Any suggestions on what we can do to improve our analysis ?