I do know a little about chairs, but without getting my hands on chairs, it is hard to determine whether a chair is old or not. You have to see the way the are constructed, how the pieces are joined etc, as different time periods (eg Victorian, Georgian) used different ways to join the legs, arms etc. To be honest, my knowledge is mostly of Georgian furniture.
They look like nice chairs, with an H stretcher. They could be late Victorian or Edwardian, but this only a guess.