1) How was Niagara Falls formed? Niagara Falls formed between 8,000 to 12,000 years ago when the last glacier retreated from this region allowing the Niagara River to plummet over the Niagara Escarpment between Lake Erie and Lake Ontario.
2) How old is it?
The Falls are thought to have formed 8 - 12 thousand years ago.
3) What is the rate of erosion on it?
The falls migrate upstream at an average rate of about 1 meter per year. This rate is thought to have been greater in the past before Canada and the U.S. began diverting water from the Niagara River to produce hydro-electric power.
4) Any other interesting tidbits of information that may be known would be greatly appreciated!
The geology of the region is what allows for the spectacle that is the falls to retreat so dramatically. The area is characterized by a Dolomite capstone left behind as glaciers retreated over an easily eroded shale. The turbulence at the base of the falls is eroding the shale, causing the falls to undercut the dolomite capstone causing head ward erosion. If you want more detail, check out this website, it seems to be pretty accurate.
Niagara Falls origins