Your height: 5'4" to 5'8" (137 to 147cm) approximatly (?).
Frame size = 18.25in/46.5cm
Comments:
Mountain Bikes: they are sturdy and designed to go everywhere including off-road. Good for rough riding. In general heavy and with deep thread tires slow on paved roads. Not good city bikes unless narrower and slick tires are installed.
21 speed: perfect to go everywhere including going up very steep hills. There are 3 front chain rings and 7 rear gears. - Derailleur: Shimano EZ Fire
Tires 26 x 1.5: medium width tires with small thread or slick, for paved road and occasional off-road.