The primary reason I didn't firewall the ratings to all 5 stars was that it gives no comparative information.
From this angle, you seemed to have captured in 3D exactly the look of the 2D cartoon. This, along with the proportions of all the body parts: eyes, head, torso, legs, tail, & mane look like they fit together perfectly.
The material for the coat looks like the best choice. The mane & tail are more difficult, but you've done well in filling them out and combining contrasting shades.
The embroidered cutie mark is an excellent touch. Trixie's expression is well-done & suits her, so your captured the personality.
I'd say Trixie herself would be quite impressed with this rendition. Phenomenal work!