Hello, I'm searching for a fic that I believe might be an old one.
I haven't read it and that would be why I'm searching for it. I remember that is was AU, Kagome breaks up with someone (who I don't think is InuYasha) she meets this girl and I think they become good friends. Kagome begins falling for this girl and then she finds out the girl has a twin who is Sesshomaru.

I would be so appreciative if you could help me find this.

is this it?

The Twin Flames Of Temptation by Axellynne Mori Reviews
Finding out Bonkotsu was cheating on her, heartbroken she decides to forget about love. But while attending University Of Tokyo she meets a pair of InuYoukai twins. She starts to have deep feelings for one, that's what she thought until she meets the second twin Sesshomaru Taisho.
Rating: MA - Universe: Canon - Status: Incomplete - Category: Chapter Stories - Genre: Action, Angst, Drama, Erotica, Friendship, Romance, Tragedy - Updated: 03-26-12 - Created: 03-05-12 Chapters: 6 - Reviews: 9 - Words: 14,115 - Reads: 2,874

It seems like it but I think the one I was looking for was rated T or M not MA

Yeah, I'm pretty sure what I'm looking for is rated T, I may have seen on FFn but I'm pretty sure it was here.

Is it possible that the author has changed the rating later on?

I have read neither the fic suggested nor the one you're looking for, but they do seem awfully similar to me, and the plot-line doesn't sound like one that would have been done many times.