My son is a little small for his age, but not to the extent of your daughter.  Are there small people in your family?  Did people in your family have late growth spurts?  Things like that are genetic too.  For example, my cousin Randy was 5’8" tall all through high school.  Finally, the summer before his senior year, he shot up (no joke) almost 10 inches.  He is now 6’7", it just took his body a while to catch up to what it was supposed to do.  By the way, he doesn’t have CAH (not even a carrier), so that did not affect his growth at all.

Robin