I like the way you captured the scene. The angle with which the characters are seen is very dynamic. Also the body poses are vivid, supple, well proportioned, and very believable and three dimensional. The shading and faces also add a strong sense of drama and vitality to the shot.



What is particularly liked is that the facial expressions tell the story in a very believable way. Cadence genuinely looks terrified, and (particularly as a little girl) is not taking being all alone in a strange new location as ideal. The fact that half of her body (face included) is shaded also conveys a sense of being overwhelmed by the new situation (and literally still in the dark).



This is where Celestia comes in. Her expression casts a very warm and non-threatening presence. Although she is technically looking down on her (implying being in a position to wield considerable dominance over her), it's coming from a position of genuine compassion, not the least of which is a sincere and disarming smile. Taking a look at her eyebrow, it also seems Celestia is taking notice of how scared Cadence looks, and is trying to first take gradual steps in reassuring her (caring about her and what she is experiencing, in other words).



The fact, also, that the half of Celestia that Cadence is seeing (from how Celestia is shaded) is illuminated by the light (the same light that is darkening the most of what Celestia is seeing in Cadence) also metaphorically speaks of what has been (and still is) a darker path for Cadence now being illuminated (particularly by a friendly and compassionate guiding light). The fact that it is the same light shading Cadence and illuminating Celestia (the part Cadence is seeing) helps support the indication that a very serious change in perspective is about to happen. It is definitely better that the shift is a positive one, since, if the location and person looking down on her are altered (particularly if it wasn't someone like Celestia), this could have been a very dark pic.



Details of the pic aside, it is personal preference for her backstory to be altered in the main canon (if done, and it is still appreciated having the book's version disclosed in the description). Having origins as an orphan tend to be overdone. At the same time, her growing up in a distant village may also have potential, since it could be where she learned to play all the games she eventually passed on to Twilight.



Since relations between pegasus and non-pegasus ponies (either earth or unicorn ponies) tend to be common, it can easily be seen of Cadence's parents being one of them. Possibly also that Cadence's parents, although meeting their needs, had a more modest income, and could only rarely afford to make the distant trip to the summer sun festival (possibly her first being in Canterlot was as an infant, and the next time being when she is considerably older). Cadence Celestia perform it for the first time, as a child, may be a basis for taking a possible interest in her and Canterlot from there (different angle than Twilight's, but still may be feasible).