:) sound like something a gang member would say to a rival(I know, Ive played too much GTA lol)
As in "This is our turf", appropriate since улица means "outdoors", also.
would you ever say "это наша улица"? And if so, when do I know when to make это-эта-эти-этот agree with the noun?
> would you ever say "это наша улица"?
Yes. For example, I point the place on map and can say this sentence.
> And if so, when do I know when to make это-эта-эти-этот agree with the noun?
Please see the guide here: https://www.duolingo.com/comment/11536858
I don't know how reliable this is, but a context search on улица = "road" says, yes, it can: