For Applejack and Starlight in particular it’s pretty special. Given for Applejack, it’s the first time in a while she can celebrate this day without feeling as sad and lonely compared to her other friends about it. And as for Starlight, well… it’s kind of the first time she can ever celebrate it. As she’s never known who her mother was til’ recently. (Keep in mind once again that this is an AU. Particularly one where the Equestria Girls films did not happen. The Sunset of this universe was killed just a little over 2 weeks after Starlight was born. And if this Sunset had still been alive, she’d be about in her 40’s/late 30’s, about in-line with the other mothers I imagine)))
Once again, AU/Alternate Universe. EQG movies/specials/etc. didn’t happen in I Dream of Twilight Sparkle. This Sunset’s a fair bit older then the Sunset known from Equestria Girls (Just appears young because she died young in a story that finished on the blog in February). Everything else like color scheme difference can have explanations such as recessive genes (Think how Pinkie resulted from a pair of grey and Brown ponies) and/or most of Starlight’s father’s traits showing up physically.
Addressed in the description. This is an AU. The Equestria Girls films didn’t happen here, and this Sunset’s a fair bit older then the EQG Sunset (Though uh… died young like AJ’s mother did)