Yep. here's her design. Technically she's actually Winterverse and Neoverse, because she's one of the dimension-travellers. However, unlike Dess and- somewhat against his will- Artemis, she spends extended periods of time in the Neoverse; so much so that she probably spends about half the year there.

She's PinkiePest, and not actually a filly- despite her appearance in G E T B A C K H E R E. She's more of Sandbar's age in relation to her siblings being around the mane six's age(s).
I hope that makes sense.

However, the main Winterverse 'storyline' (term used extremely loosely) takes place when she is already full-grown.
Once again, I hope that makes sense.

AKA she's younger than the triplets.