Do girls like tall or medium height guys?
Tall. Almost every single time. Short (or "medium") guys get ignored by women because most women do not want the default/mediocre in a man. Women tend to want the best, most elite of men (this is called "hypergamy") and when it comes to physical characteristics, tall is always better than shorter.
When it comes to North American and European men, "tall" among men would be at least 6′1″/185cm. Anything below 6′0″/183cm would at least be, as you call it, "medium" and not an attractive or advantageous trait whatsoever in attracting women. Being mediocre in size is no more attractive to women than being right-handed or having two eyes or having five fingers on each hand or being nice.