I've been on hormones for between 4 and 5 months now (I didn't note the date I started) and since then my measurements have changed. My underbust has decreased from about 35 1/2" to 34", my waist has increased (ugh!) from 30" to 33" and my hips have increased from about 35" to 37".
Also, recently, I've noticed a change in the contour of my face. It feels different somehow. My arms too have noticeably shrunk a little, and my legs seem fuller. To the average person these changes aren't noticeable, but seeing and living in my body, I definitely notice.
Everyone's bodies react and change differently to HRT (as with any medication) so don't be discouraged if you aren't having similar results.