On path exception - is my solution acceptable?

Hi, I am new to programming, and as I saw few people also had problems with creating the OnPathException. When I was checking what other people did, most of them used loops which I don't know yet. Therefore I tried doing this my own way. My code works, however, I feel like it's not the best solution. So first I created OnPath method in the Path class:

 public bool OnPath(Point point)
      {
        return point.Y == _path[0].Y;
      }

I didn't check every position in the _path array since if Y of the tower is the same as the Y of any map location in the path it's always on the path. (I am aware that it only works if the path is a straight line but I wanted to keep it simple. )

Then in Tower constructor, I wrote:

public Tower(MapLocation location, Path path)
    {
      if(path.OnPath(location))
      {
        throw new OnPathException("This tower is on the path!");
      }
      else
      {
        _location = location;
      }

and I created new exception:

class OnPathException : TreehouseDefenseException
  {
    public OnPathException()
    {
    }

    public OnPathException(string message) : base(message)
    {
    }
  }

And to my surprise, it works. However, I would like to hear from more experienced people if this code is acceptable. Should I change it or leave it? Any tips?

Cheers!