I'm 18 and will be 19 in feb and i am still growing when do girls stop growing?

Varies: Most stop at 15-17, or about 2.5 inches after their first menses. The open growth centers of the long bones permit continued linear growth.The hormones that bring on the start of menses begin signiling the growth centern to close. An x-ray of the wrist and hand can determine wether additional growth is possible.When the growth centers close, linear growth stops.

Depends on puberty: The timing when growth stops depends on the timing of puberty. Generally, a girl may stop growing about 2 to 3 years after the onset of puberty. So girls who enter puberty late will generally grow longer (and often taller) than their more precocious peers. The timing is not the same for every person.