Are kids getting shorter and shorter each year?

Im 13 I'm 5 feet 7 inches tall and I'm going into 8th grade this year. At the start of 7th grade I was baffled at how short the new 6th graders were. Not meaning to be rude but they looked like they belonged in 3rd grade. In 6th grade I was 5'5, the new kids are like 4'8. They seem to be a lot ruder too.