Welcome Sandra,
What you are experiencing is entirely normal, even predictable. The good news is that is something already knew and there are many ways to overcome this.
Parrots are highly intelligent among birds, the bigger the parrot the more demanding their intelligence is. Lovebirds are an exception among the small parrots however, they have an intelligence/sensitivity more similar to medium parrots than to small parrots or parakeets.
Intelligence and sensitivity are much linked and both are traits related to animals with a long life span and a complex social arrangement respectively.
Scientific experiments with African Grey Parrots (particularly one AG named Alex) demonstrated that medium size parrots can express the intelligence of a five to six years old child. I would take lovebirds for a species with a three years old child cognitive system. That said, do not underestimate your bird.
It seems to me that your 11 months old lovebird is going through puberty. It is right on this age that puberty happens and the side effect of an hormonal lovebird is aggressiveness. After sexual hormones go down, she will be a lot more receptive.
Another important aspect you night to considerate is that you have a female. Lovebird females are way more territorial and aggressive than males. Also, in her point of view, when you took out her mirror, you eliminated her partner. It would have been better to do that out of her view. Even so, the absence of the mirror frustrates her sexual impulse, so even if it was done in disguise she would miss the mirror.
I´ve never put mirrors to my lovebirds and budgies so I don´t know the best approach right now, if it is better to put it back or just keep her without the mirror. Maybe some other members can help.
Regarding the biting issue, you might have to be a lot more patient with her during puberty and there are several threads on the forum that address how to interact with biting birds in an efficient and healthy way for both birds and humans
