Tough Situation as a 20 Year Old

[Elijah Faas]

So this last July I purchased my first duplex using traditional financing which has been going very well. I now have found a land contact deal for 170k purchase, 6k down, 4.75% interest, and a 5 year balloon. Comps in the area are around 150-160k. Rents should be around 1500 and there is also a detached garage that could be rented out for ~$100 so the whole place should cashflow around 300 a month doing a long term rental with reserves accounted for.

Is there something I am missing? This seems like a no brainer for 6k down but I just need some opinions. Ideally I could talk the seller down to 165k pp and 4.5% interest. Thank you for any input!