FicWad

Well, you have to keep in mind that this is AU.
That said, You're right. Ginny didn't a huge role in the books, but to compare her with Colin? that's a bit too much. Colin was in a position where he didn't have inside knowlege of things most of what he knew were rumors...like almost every one outside the trio, Dumbledore, The Order, Voldy and the death eaters.

Now, Ginny is a Weasley. Most of her family were members of the order...
She was bound to know certain things that Colin Creevy wouldn't ever know. She might not have been a main part of the books.Now, the books are from Harry's point of view, but that doesn't mean he knew everything that happened everywhere or that nobody else knew anything.

Ginny is also Harry's love interest, her brother is Harry's best friend, and Hermione is also her friend. Ginny was at HQ with the rest of the Weasleys, went to the DoM with Harry and the others, not to mention than in this story she lost everyone except those three, and when she found them again she stayed with them and helped with the Horcrux hunt. It would have been very stupid of the trio not to tell Ginny what was going on. You know, Hermione IS part of the trio and she is anything but stupid. True, Harry wanted Ginny to stay safe and probably tried at first to find somewhere to hide her, but she was the only other Weasley left other than Ron, And at least in my mind, and my story, after losing their family they wouldn't want to be apart, and with Snape at Hogwarts and the Ministry under Voldemort's control? Where else could she have gone?

...okay, wow, sorry for the long rant, but really Ginny had a bigger role than most realize at first, so she she shouldn't be put in the same level as Colin.