There are a lot of great small frame bikes, but a lot of them are not going to be found used. So, that is good that you are looking new. Also, go get fitted. I thought I was in your range (same height as you) and I am a 47 cm girl on my Trek and a 50 in giant's OCR series. Just really depends on the geography. I am all legs, so I take a taller bike, but you may be surprised!