I purchased my single family home from my parents in 1988.I was born in this house in1960 and moved out in 1982.it always had a rock wall as a bound

You will have to begin your work with a good record examination of the background title, and probably you will have to have the property surveyed.  The important question is whether the rock wall was built on the line and whether it has ever been moved.  If your title examiner and your surveyor conclude that the property was adequately described when your parents bought the place, and the rock wall was placed on the line, you should have a strong case.   You may have a strong case even if the rock wall was not built on the line.  Most (probably all) states have laws dealing with "adverse possession".  This is a concept a bit like "squatters' Rights" -- if the owner of land allows someone else to occupy his property long enough without protest, then at some point, there is a presumption that the occupier in fact owns the property.  So, long years of possession may entitle you to claim good title to the disputed land even if the wall was built beyond the true line. Be advised, however, that the rules of "adverse possession" do not apply to governments.  If the adjoining land where the school is to be built has been owned by the city all this time, you can't claim adverse possession against it.  See a good real estate attorney in your area and have the background checked, and have your own well-qualified surveyor check the accuracy of your own description -- and the accuracy of the city's survey work.  Good luck!