I’m 11 days post op. I love the shape and size of my crease but I heard that it will decrease. Is that true? (Photo)

Yes
On your photo, I can see there is still swelling and as healing takes place the crease size will be smaller. I can't say whether it will go down 50% or not but crease will become smaller. It also depends on the thickness of your skin. If you have thick skin crease size won't change much compare to thin skin.
Dr. Andrew Choi

hi,
if you are only 11 days post op, your fold height will continue to settle but not sure if it is accurate to say it will decrease by 50% at 3 months.  if your surgeon set the fold at your desired height, it should setting to that point.  hope this helps.

dr kahng

Based on the photos, you still have swelling involving your upper eyelids, which tends to exaggerate the appearance of your crease.  For a better idea of your permanent result, wait usually until 6 weeks.