Fences and Walls: I Have a Witness That My Fence is More then 30 Years but the City What to Take It

My question involves real estate located in the State of: nj

I bought my home 2 years ago from the children's of someone that died

This home is 60 years old.

The house have fence that go out from my land line but I have neighbor that agree to be my witness that is there 30 years from the time she was young.

Now the city want to build home next to me and to take that part.

Can I stop them?

Is wetness it's good enough or I have to get something else

Thanks

Fences and Walls: I Have a Witness That My Fence is More then 30 Years but the City What to Take It