Woohoo! You must have been on cloud 9! My daughter was 6 when diagnosed and all the doctors did say that although it was unlikely, there was a chance that things could improve with further growth. From what I have read since, I figured that was like winning the lottery and I'm glad to hear that your daughter has!
I suppose there is a chance that the xrays were misread; if you request a copy of the xrays (you may have to pay $10 or so for it) you could take it to another ortho and ask them to measure the curve for you. That would give you comfort if they came up with a similar size curve. I also have to say, I think I agree with your pediatrician that you shouldn't wait a full year for the next set of xrays. Hopefully her new curves will hold (or even continue to regress!), but scoli is infamous for its sometimes big jumps in relatively short periods so I wouldn't want to take the chanced of letting 12 months go by.
How great it is to hear your good news.
daughter, 12, diagnosed 8/07 with 19T/13L
-Braced in spinecor 10/07 - 8/12 with excellent in brace correction and stable/slightly decreased out of brace curves.
-Introduced Providence brace as adjunct at night in 11/2011 in anticipation of growth spurt. Curves still stable.
-Currently in Boston Brace. Growth spurt is here and curves (and rotation) have increased to 23T/17L