Gwen Delta appears similar to her Prime counterpart when she was 10, albeit with different clothes and an altered hairdo. She is identical to the canon Gwen.
Gwen is generally friendly and tomboyish. She often tries to help Ben out, and the two share many common interests- this is a sharp contrast to how their Prime counterparts interacted at this age. That being said, the two still butt heads occasionally.
All of the events of the Ben 10 Reboot up to but not including Omni-Tricked occurred in this dimension and therefore to this Gwen.