Still obsessed with that idea of yours?

behind a door marked "Skuld's Room", a goddess sulked.

It's "Skuld's LAB"!

Her large brown eyes closed as she concentrated on her earliest memories.

Don't have any newer, clearer ones?

He wasn't going to be her brother-in-law, but at least now they could 

become friends.

What do you mean friends? He outranks you now.

Now that she knew the truth, she'd show proper respect.

Took her long enough.

"When Skuld will be very young, she will be sent back in time so that she
can stay with her mother and be available to help with the trials we have
and will face.

Here's the biggest hole in your fic. Just how young do you mean? And how 
much help can she be at that age? Sorry, not believable enough. This idea 
has enough of Sailor Moon in it to be scary!