Typically the head tube on ladies bikes is longer than on a mens bike (but not always). You will want to check the linkage alignment, for instance on a Columbia springer the top plate on the mens fork is essentially flat but the ladies style is bent in a "Z" to deal with the taller headtube. If the linkage will not be an issue or you can work around it, and if you need to adjust the steerer tube you have 3 options that I know of.
#1: Cut more threads on the steerer tube,which requires a special tool. Once this is done you just cut down the steerer tube. I would suggest threading down the upper headset cone and use that as a cutting guide, file the end after cutting, then when you spin it of it will clean the cut a little for you.
#2: Cut and weld the steerer tube into a shorter version. A short section of handlebar (±1") and split down it's length will work nicely as an internal sleeve. bevel your cut edges prior to welding to expose more surface area. Make your cut low enough that you will still be able to insert your stem to a depth that will work for you.
#3: I have seen some guys file the threads from the top bearing cone so it will pass over the unthreaded area of the steerer tube, then they stack spacers on until the threads are reached, and add headset nuts from there on up. Never done it, and my only comment would be to make sure you have the headset adjusted properly and the lock nut is good and tight. My concern is that because the upper cone is not in contact with any threads it may wobble.