Isnt my SIL's daughter too young for this behavior?

I am married for 7 yrs.To start with I have ok inlwas (not that bad). I am not into any politics with them and my husband wont let them to play any. At the start of our married life I saw emails form my SIL and FIL to my husband saying he is only after his wife and then he is not giveing attention to them and my husband replied by saying"I dont want anyone to tell me what or what not I shd do with my wife". I wont forget this for the rest of my life.
From then they understood that trying to create drifts between me and my husband would be a harm to their own relationships so they are always fine with me. My husband loves my inlwas and sil as I love mine ,fair enuf.

But Iam here to discuss about my sil's daughter. My sil and her daughter were always like a family to me,not to mention buying them expensive gifts like second hand car, gold waist band etc, becuse my pils would ask my husband to.But I dont have any problem with that as my husband spends on us(me and our son) but taking places every holiday and thats what makes me refreshed. My sil's daughter sometimes behaves like a big person ,like a big sil! and she is 14 now. I mean...here are some eg:

1. when I was newly married, she was eight ,just a little gilr i adored. Once i made a chutney for chapati and I made in 1 min. She asked "Atta (thats what Iam to her ) what is this its so dilicious"...I said " I mixed chutney power to yougurt thats all". She says" Well then so you did do anything so gr8...i could do it"...and she was 8 yrs old!!!!

2. Last time I went to India my husband bought me a bag, I thougt better give it to her as it better suited for her and it was very stylish so I said "Take this ...its for you" then just my husband came and said" didnt I buy that for you?". Then I said"It will look better on her" and then she shouts " I dont want things bought for someone else". I was like ....struck!

3. Now when ever they call us...she asks my kid(she is very close to him) "Do you want me to come there?" we stay abroad. And she talks very tactically to me about her studies then reveals" I want to study abroad after 10th class, howz education in your city".....Who is teaching her?????.I am almost stopping to believe she was my tiny sweetheart sometime ago!!!


Also my SIL once said to my hubby" Yeah all her friends go to europe for holidays......" I really dont know what she meant and I dont want to think. Its not very easy to just send someone to europe for holidays!!!! and the other time when I thought I was wearing a good saree...she says" Its ugly...go change,my husband was already in a bad mood so he didnt care but I cried a lot and I said this to him after some days...and he just listened to me and said"Dont feel bad" and thats all. Thats enuf for me.

Iam 100% sure that the girls marriage will be on us and we will even pay the dowry and other things. Her dad is a good person earning enuf but he is in his own world of his family and relatives but I cant complain.

Any say friends?