Knowing what you know is a significant part of learning and a component of many learning theories. In this work, we explored 3.5-year-old's metacognition of word learning to understand children's confidence over recently learned novel words and explore the experimental conditions in which young children can show metacognitive abilities. After novel words were taught, children were asked about the meaning of words two times. Prior to asking the second time, an opportunity to seek help was offered so that the second word meaning inquiry could be modified. We coded the amount of time children took to select the referent during the first time they were asked the question and examined the relationship between the accuracy of their first-time referent selection and the subsequent help seeking. When children made an incorrect response, they were slower and were more likely to ask for help compared with when children made a correct response. Thus, even though children at this age are not able to report their own learning explicitly, the information-seeking measure showed that they were sensitive to their metacognitive states. We discuss the implications of these findings for theories of the development of metacognition and for word learning mechanisms in general. (PsycInfo Database Record (c) 2025 APA, all rights reserved).