Apparently, I am late to the party...
1. Reaching a ceiling has different meanings. One sense is the discontinue rule, which means that the student had the number of items incorrect (usually in a row, or within an item set, depending on the test) needed to trigger the discontinue criteria for that subtest. Another is the test ceiling is too low, meaning that there is reason to believe that the student's abilities were underestimated/truncated by this instrument, because there were insufficient difficult items to spread the upper extreme of the population. Typically, this is indicated either by failure to trigger the discontinue rule (see the previous meaning of ceiling), or by obtaining the maximum possible scaled score (on the WPPSI-IV, that would be a 19 on the subtests).
Your child's subtest scores do not reach the ceiling in the sense of max obtainable score, but it is possible that the discontinue rule was not triggered prior to running out of items. That would be a question for your test administrator.
2. Score profile: It would appear that your child was given the WPPSI-IV subtests comprising the GAI only, which is reasonable in a GT assessment, but does not provide the fine-motor processing speed data that was mentioned above by Portia. As she points out, the BD score is noticeably lower than the other scores, and does suggest that further investigating her motor and/or spatial skills might be worthwhile at some point. She is also very young, and in her first formal school experience (it appears), so this may indeed also represent lack of exposure. I would keep an eye on it, though, especially as asynchrony in fine motor skill can be a key factor holding children back from various forms of substantive GT interventions, both in the primary grades, and much later on.
3. Achievement testing: with regard to the KTEA-3, it is a norm-referenced instrument, designed to provide information on one's standing compared to age- and grade-peers (depending on which norms are used). It does not comprehensively sample the skills expected for each grade level, which is why it cannot be used to determine grade placement (you would need a criterion-referenced instrument, or a curriculum-based assessment, for that). On the plus side, it does highlight the outlier status of your child, which can be helpful in advocacy for explaining that, for example, the child who is at the 98th %ile is one in 50, which means that, in a school with 4x25 = 100 kindergartners, there would be expected to be about 2 students available (including her) to make up a reading group for her. So no, "going deeper" on the existing grade-level curriculum materials probably won't meet her needs.
