What are your opinions on this duplex?

[Jake Michaels]

This is on long island. I'll be ready to buy a duplex to live in/rent in about 5 months. Until then, I'm just researching and trying to pick out a few good buys for experience. I'm wondering what you think of this one:

https://www.zillow.com/homedetails/7-Reed-Dr-Deer-Park-NY-11729/32620876_zpid/

With 5% down mortgage + tax would be around $3,300. I could rent the larger portion for $2500 compared to comps. This leaves me with a deficit of $800. My current apartment is $1500 a month so having to pay $800 seems great. Even if everything goes wrong it would still be less expensive than my rent as well as something I keep.

I figure in 2 years or so I would move out and rent the smaller portion as well.

I'm just making sure the Math + my logic follows. I'd rather make stupid mistakes on something I'm not actually buying. What do you think?