We need Maury from the Maury show to help figure this simple situation out. Mrs. Celestia over here is making a big fuss about Athena's appearance. And I'ma say it now, Novo isn't a part of this problem. She's confused because Athena (when she was a baby) didn't look like Tia not one bit. However Celestia with her disoriented brain forgets what she looked like 10,000 years ago, and that's understandable (I mean like, I can't remember what happened yesterday…). Even though Athena uncannily resembles Queen Novo in a way (and before Tia was pregnant with Athena, they did have some sexal relationships), she actually bears semblance to young Tia's pink and white color scheme.
But then again, since Discord is in the mix of this polymorus relationship, who knows if he cunningly switched up some things in the womb. 👀

Anyways, Celestia caught onto this peculiar appearance of Athena when she was a year old. Since she was born (or hatched) completely white, they all didn't know what she would 100% look like. Thus, once her color started kicking in (with it primarily being pink obviously) a year later, Tia started growing some suspicions. Well actually, her first suspicion was when she saw that Athena was born with a beak… but she didn't think too much of it (because it's Discord's child…y'know…Tia should've just kept it at that but NoOo). But then her second suspicion was when her child was just not forming a color scheme that resembled her current one, which isn't something to be too confused about… but this is Ancient Celestia we're talking about. She's old and more than likely always tipsy. She's just been through it, and is now bothered by her daughters color palette (not in a shameful or bad way. Just in a way that Tia's brain is just very befuddled).

Regardless, Celestia wasn't going to be upset if Athena ended up looking like Novo, maybe just a bit confused (like always) because Tia was the one who birthed her. And when Novo and she were mingling about, there wasn't any genderbending to be had in the midst of their lovemaking. They were just raw lesbians making out (w/ Rain Shine too 😌). I guess Celestia just needs some reassurance that Athena is her diddly darn child, because with all the sexual relationships she's been in she just doesn't know at this point.

(And the baby is always gonna look like you Discord!)

This was just a nonsensical submission, nothing too extraordinary 😆