The allowable re-test interval with achievement tests is a minimum of six months, with the same instrument. There is no wait period if it is a different instrument, such as the WJIV (if you just had the WJIII), KTEA-3, or WIAT-III.
At this age, there may be gaps in her achievement due to lack of exposure/instruction, in addition to the leaps in skill acquisition that one often sees in GT (especially young) kids. Do you need the achievement scores for anything else, in the near future? If not, there is something to be said for waiting, as the scores are likely to be more reliable and informative as she becomes older and more tolerant of test conditions.
