She was practically inviting you to fuck her.
The IOIs, the DLVing her boyfriend, and practically saying he isn't worth anything. (The stuff about how she was "too dumb" to dump him etc, is pretty much a signal she wanted you to prove you were much better for her than him, e.g. by fucking her from here to heaven.)
You should have escalated, and I bet you could've gotten her by the weekend if you played it right.
Now, as chief said, you've missed a big window of opportunity, so I wouldn't be surprised if she doesn't give you one of those again.
But be watchful for it.
Like mystery said "If you think you could have, you could."
This is a classic example.
All the right signals from her, but you didn't follow them up
You'll get better at it
Forget about the Boyfriend, he's got no value in her book, no boyfriend destroyers needed.
The invitation to hang at her place was a real come-on from her side,
Regarding her friends, it can't hurt to game them a little as well, make sure they like you (social proof) at least.
If you get good with her friends, she'll be even more lusting for you, especially if they start considering you sexually attractive, Women talk.
Hey, man.
Next opportunity; you grab it.
here's a little Could Have list:
You could've turned the hug into a kiss,
you could've started physically escalating in the library; e.g. stroking her back, probably even playing with her hair, or even escalate all the way to the Kiss by running the conversation from Valentines day to how you should treat women, by running a little story perhaps, "This is how to celebrate Valentines Day, (Describe romantic things as you do them, like "you look her in the eyes, and notice how nothing else matters in the whole world, etc." lean in for Kiss if she doesn't resist, then go for the Kiss)" then you should consider a change of location, after building up some tension again (the kiss can be a real release in tension if nothing follows it)
You shouldn't have mentioned her Boyfriend, since she didn't seem to care about him at all.