My niece doesn’t like me

I need some help with this situation. My 10 year old niece does not like me at all. This is my husbands sisters daughter.

I don’t know why. She gives me a serious attitude whenever I am around. She won’t say hi to me, she won’t even make eye contact with me.

So I was always really close to her and her siblings. We used to do sleepovers, she was the flower girl at my wedding, we used to have so much fun. She was really such a sweet girl. She was always very rude to my parents, but I figured it was because she didn’t know them too well.

Then my son was born. That’s when things got weird. Whenever we would go there, or she would come here, she would get so excited to see him, that she wouldn’t acknowledge me. I figured that’s fine, she loves her cousin. But then she just started getting mean. I was babysitting her one day, and she asked me why my house is so filthy. My house is not filthy, it just has toys everywhere. I was like oh it’s just toys! And she’s like no, there’s dirty dishes in the toy box. (My son put his sippy cup in the toy box)

She’s asked me multiple times why I still look pregnant even tho I already had the baby.

Whenever she comes over, she walks in my house, says “where’s Ryan??” (My son) and I’ll tell her he’s napping, and she just rolls her eyes.

Does not thank us after we give her a gift

I can go on

She only acts this way with me. Not with my husband.

Is it a phase?? Will we be closer once she’s older?? Her older sister never acted like this towards me. Her older sister is 13 and I’ve had a great relationship with her since I’ve known her. I just don’t get it. I’ve always had a great relationship with all my aunts growing up, i hate that she doesn’t like me