If she is a mainland she is very small, Xena was sold to me as a 'mainland (mixed blood)', they admitted to have been maintenance feeding, 1 mouse every 2 weeks for a year. Being past 3,5 years she is now 12ft (Having a
massive spurt currently, grew nearly 2ft in a matter of weeks), which is about the same as a average dwarf at that age, and she has been fed well.. So i really think she has a fairly large % of dwarf blood in her, suspect she will end up on the large end of of dwarf size unless she keeps this spurt up for a year... I found a picture of her where she was around riverruns age, she was quite similar in size to her at the same age, but she was already being fed adult rats(it looks like a big meal, but it went down and digested rapidly).
On this picture, Zuko is about 1,5 years old, Xena is 3,5. Zuko is 100% mainland. He is already half her weight, and only 3ft shorter (the picture does distort as he is closer to the camera).