Yes being held back 2 years would be extreme .However if your school uses august as a cut-off as I belive many schools in nj and maryland do as opposed to long island where december is used then over a 2 year age difference between players on opposing teams happens more often.
August birthday 1996 child held back 1 year equals 2016 year of graduation for most maryland schools.
October 1998 birthday equals 2016 graduation for most long island kids.
So by a child being held back 1 year makes that child more than 2 years older then many of her competition.Nota level playing field. | 
