Do you have to lenghthen the stirrups and check the girth?

NO you do not have to lengthen the stirrups. In fact the girth is completely separate from stirrups. Just throw the stirrup over the pommell or horn, and adjust by cinceh or girth buckles. The western saddle has a circle cinch, that you adjust to make the daddle snug. The English saddle has two straps like belt buckles that you tighten to get the saddle snug.

um yh but u shouldn't really take ur feet out the stirrups when u do it(at least with an English saddle i dunno about western) all u have 2 do is like lift ur foot up a bit and if u cant do it like tht and u need to take ur foot out the stirrup then take BOTH feet out otherwise if ur horse spooks or summin u will b dragged along