Virtual Reality (VR) has the potential of becoming a game changer in education, with studies showing that VR can lead to better quality of and access to education. One area that is promising, especially for young children, is the use of Virtual Companions that act as teaching assistants and support the learners' educational journey in the virtual environment. However, as it is the case in real life, the appearance of the virtual companions can be critical for the learning experience. This paper studies the impact of the age, gender and general appearance (human-or robot-like) of virtual companions on 9-12 year old children. Our results over two experiments (n=24 and n=13) tend to show that children have a bigger sense of Spatial Presence, Engagement and Ecological Validity when interacting with a human-like Virtual Companion of the Same Age and of a Different Gender.