Am I being a good sister to her?

The dilemma at that age they are more concerned with how others see them. rather than how they fell about them selves.
she will have to learn to think for her own sake. one of the harshest lessons of growing up.

I think you are a good sister, she is at an awkward phases and still coming to terms with her body and figure.
If any of my sister's friends said stuff like that to her, I would have a serious talk with her, I can be scary like that ;)
But you're doing good, don't feel guilty about someone else's insecurities.

this Lisa friend seems toxic. she's not a friend. she's only using Anna by putting her down to boost her own ego. Lisa probably has self-esteem issues and by putting down Anna, she feels like she's conquering her own inner demons. it may also be that Lisa gets put down at home. I don't want to assume things but maybe Lisa's mother/sister/someone in her family puts great emphasis on a person's worth by judging the way they look.

i know you can't control who your sister hangs out with. I'm an older sis like you and I have a younger sis myself. trust me, growing up for her wasn't easy. I was a bit of a tomboy then so I was always there if she needed me. if I had to resort to physical violence to protect her from the boys throwing things at her or if I had to cuss out the girls making fun of her, I did. I made sure they cried their eyes home. I know it's hard for some people to understand but as an older sister, you feel like you're a bit of a mom when mom isn't around. so I think you're just doing fine as an older sister. it's sad these days because most older sister's don't give a hoot about their younger siblings as much. the only thing you can do with Anna is be a role model to her. try to take some time to spend with her. compliment her and encourage her in the things that she does. and about the whole breast implants thing.i'd slowly educate her about it. I'd say that a young girl like her is still growing. some girls are late bloomers while others grow at a later age. a friend of mine didn't develop larger breasts until gr 11. so for her to get breast implants at 16 is too early and dangerous. women mature until their early 20s. so she has plenty of time to grow. aside from that there are health hazards, one of them being the increased chance of her getting breast cancer after getting implants. I guess what I'm trying to say is to help her make an educated decision. whatever it is, you won't be able to control what she does with her body as it is hers. the only thing you can do is to tell her what her options are. I'd also bring it up casually and try not to lecture her on it either. because once you start going against her opinion the more she'll retaliate.

i know some people will think this is extreme, but if you can, try to minimize if not cut Lisa out of her life. it's obvious that this girl psychologically affecting the way your sister thinks about herself. it's not healthy to be around people who will put her down. what Anna needs is encouragement. if Lisa doesn't change her ways, talk to you parents privately about some of the issues that you have with this girl and how she's affecting Anna. try not to get your parents too alarmed about it, maybe just an fyi type of thing. you're not tattle telling but just voicing out your concerns. maybe tell them you don't want Anna that you told them but you're concerned and thought that they should know what's going on with Anna. I do this when I feel like I don't know what to do with my sis.