I need some help please.

I am looking at ordering a new Trek WSD, probably a 2.1 or a Pilot 2.1 but I am confused as to which frame size to get. I am 5’4”. The dealer suggested a 52 cm.

I have two older road bikes right now. The one I ride the most is too big for me. It has a 31.5 standover, 22” tube length. I can straddle the tube when standing, but just barely and I am stretched out too far.

The other bike is an older Georgina Terry. I am not sure of the frame size but the standover (28.75”) and tube length (19.5”) are almost identical to the 52 cm Trek 2.1 WSD. I have a good 2” clearance on the standover. The wheelbase on the Terry is 1” shorter than the Trek. When I first started riding this bike, I felt like I was too “hunched up”. My knees would come up and hit my arms and when I was on the drops, my forearms pushed up against the top bar. I added a longer stem and that took care of those problems but it puts me out over the front wheel too far and the bike is very unstable.

I have done a lot of research on bike forums and the Trek website, and they state that for someone my size I should be looking at a 47 or 50 cm frame. I am not sure that I want to buy a 52 cm bike considering that it is the same size as my Terry, let alone a 47 or 50. Am I missing something?