Overly confident 13yr old – Help needed

[thedeepend]

About a year ago my partner and I began fostering our 11yr old niece on a permanent basis after her mother was no longer able to care for her.
When she arrived she was a very overweight child who had low self esteem and no confidence but at the same time she was polite and had impeccable manners.
Over the past 12 months we have worked on improving her social skills and she?s enrolled in several clubs such as Brownies, Dance etc. She has also lost around 2 stone in weight and generally become a happier and more secure child.
The problem we have is this new found confidence has now crossed a line and she?s now all of a sudden become very over confident. This includes answering back, being a know it all, speaking to adults on their level, challenging teachers and even making catty comments about other children in her class.
We desperately need to reign this back in but don?t know how. Prior to taking on our niece, neither my partner or I have had children so the past year has been a huge learning curve therefore any advice from you guys (the experts) would be greatly appreciated.
Cheers

This sounds like fairly typical teenager behaviour; maybe ask again over here? (Mine are male, and past teen years...)

I think we were bracing ourselves for teenage tantrums and the challenging of our authority later down the line, but she's on recently turned 11. Even her teacher is now telling us that this needs to stop but we don't know how to get it under control.

In your post you say she is 13?

Still at 11 the hormones can have started.
You need to speak to her calmly and in an unchallenging way. I would suggest reading "How to Talk So Teens Will Listen and Listen So Teens Will Talk" for some guidelines.

Also try to get her to show empathy and understand how other feel.

Reading "Queen Bees & Wannabes: Helping Your Daughter Survive Cliques, Gossip, Boyfriends, and the New Realities of Girl World" could also help you understand girl society at this age. BTW my daughter's little group of friends had one girl whose mother died then she announced she was leaving their group as it was "my one chance to be popular". Needless to say when sympathy about her mother wore away her original group aren't so keen to have her back.

Has she ever had any form of counselling after having to leave her mum? It's bound to have had an impact on her and may only be coming to the fore now hormones are moving. Maybe her school have a counseller she could talk to. A lot of it sounds like typical teenage, but if it's starting to cause problems in school then yes, she needs bit of help.