Traditionally that height was meant to allow the placement of furniture under the sill.
Common height of a window from the floor.
Window sill materials traditionally window sills were made of wood stone granite brick or other locally available materials that made their construction convenient and inexpensive.
With 9 and 10 foot ceilings it s common to use taller windows that fill the space proportionately but beware of added costs if your windows require different framing for the ceiling above.
Windows typically start at 3 feet above the floor to allow furniture to sit below the window sill.
Unless the windows are specialty or custom it should be relatively easy to locate common window sizes that your home needs.
Similarly many windows can be set lower than the common height of 3 feet above the floor.
Window height varies by location style and period.
A side note to these measurements is that a manufacturer adds a half inch to these measurements giving them plenty of room for installation.
Window sills can be lower but may require safety measures.
If you adjust the height of the installation you may be able to opt out of using this specialty glass and install regular window glass instead.
Window placement is greatly varied as exemplified by the narrow windows placed real high in 1950s tract housing and the low and tall openings located almost on the the floor in suburban mansions of recent years.
A 2426 replacement window has a width of 2 feet 4 inches and a height of 2 feet 6 inches.
Window and window sills are installed at a standard height generally accepted by most contractors unless other design considerations come into play.
The location of the windows is critical when choosing the glass used.
Standard window sizes for the bedroom are generally 24 inch by 36 inch 24 inch by 46 inch 28 inch by 54 inch 28 inch by 66 inch 28 inch by 70 inch 34 inch by 46 inch or 34 inch by 62 inch and are either single hung.
Most homes have 9 10 ceilings that are new builds at least on the main floor and 7 windows are common.
Some windows based on their height from the floor or ground must be made of tempered glass.
I would check on the height of the doors in your home because you will want the height of the windows to set up nicely with the door heights.
The truth is that there is no normal height of a window from the floor.