My brother in laws fiancé never says hi to me and is just rude! What should I do?

I feel like she hates me, but I can’t understand why! I’m nothing but nice to her. EVERY TIME I see her I say hi and scan the room with my eyes because there’s usually a group of people and everyone says hi but her. One time I thought maybe she didn’t hear me so I actually looked her in the eyes and said hi and she looked away. It made me feel like am I crazy? Did she not hear me again? This has happened 3 times out of the 4 times I’ve seen her.

The one time I said “hi! congratulations” because they had got engaged, she just said “thank you.” Another time I walked over to my brother in law and her and him and I started talking and she literally left and went to the washroom?

I’m always the one to say hi first or communicate I’m some way. No one notices it either!!! Its just frustrating. I’m not a rude person. In fact I super from major social anxiety so it’s actually really hard for me to speak up and do things like this. It’s to the point where I don’t really want to be around her because she just makes me feel uncomfortable. Things like this actually bother me because ideally I would like to get along with her. Were basically family now. But I feel like she doesn’t care to. She came to my daughters 3rd bday without a gift...which I thought was rude because she ate food and cake...Before this girl his other girlfriend and I weren’t close but when I became pregnant she bought so much for us for the baby was super helpful, constantly offering advice and help..

I can’t even say she has the same problem as me either because she is so talkative to other people and she works a job where she’s super talkative. I see her commenting all over BOTH of my sister in laws photos and my husbands cousins photos. I honestly feel like she’s trying to one up me? But idk if I’m crazy lol. She’s just rude to me! And ONLY me! She’s so nice to my sister in law...

What do you think about this? Am I overreacting? Should I even care? It just makes me sad honestly...shes going to be my daughter aunt I wish we had a better relationship 😢