first gear problems

Ok so I was driving on the interstate for about 2 hours to my moms house When I got the her town and hit the first stop sign my jeep was acting like it didnt shift all the way down to first. when I began to drive its just like starting in 2nd gear. It works fine if i manually put it into 1st then move the stick through the gears. Has anyone had this problem before?

Well after cooling off for a few hours my tranny is acting just fine now and shifting smooth. I have 116,000 miles. I think I changed the tranny fluid around 100,000 but I can't remember. Should I change it now or not? I dont think I would flush. Probably drain and fill and maybe a new filter if it's nasty.