My brother-in-law's wife is rude.

Long story short: I have three sisters that can't get kids while my brothers does not have any problem with that. And everybody who knows me, knows that about my sisters. 
My brother-in-law's wife is lowkey mean to me. I can't describe her more than saying that she is... weird. People have start to notice that she is basically is copying everything I do. But I don't have any problem with that. I did only mention it because it will maybe describe her as a person. My problem with her is, that she is constantly asking my husbands dad about when I am planning to get kids(it's not her business). and I know that she talks behind my back and are saying that I can't get kids blablabla. And she is irritating me on snapchat, she is sending me videos about her little boy all the time. Even when it's not something to see. And i do not reply to her. i have done it. But not in a good 5 months and she sends like every other day. 
Is it me who is misunderstanding the whole shit or what? What do you think I should to about it? 
I come from Denmark, so sorry for my bad english.
Edit: when I did say that she is mean I meant that she does not like me when I get happy or when good things happens to me. And when I succes with things or when I just did promote as a chef she did not even say congratulations, she just did ignore it. And she did ask me on snapchat is she could get a discount on the botique out of the blue and I did say to her no sorry i cant and she did answer with: K.