I don't think my boyfriend's mom likes me

I've been with my boyfriend for 10 months and have never met his mom. I've met his dad on a few occasions but not his mom up until recently. His sister was having a birthday party. She turned 15 and my boyfriend brought me to her party. His mom immediately ran and hugged him. And started asking why she hadn't heard from in 6 months. I'm just chopped liver I guess.

She says nothing to me until he says "Mom this is my girlfriend." I could immediately tell by how she looked at me that she hated me. She said "Oh. Is this the one who's been taking up all your time from me? Well, I'll let you know by the end of the day if I approve but no one is good enough for my baby mom." My boyfriend said he was gonna go wish his sister a happy birthday and he left so it's just me and her and she starts drilling me asking what I see in him and to just know that he's her baby and stuff.

I tried to be nice but she kept saying how no woman is good enough for him and I will never be good enough. Then told me to remember no matter if we get married or how many kids I give him, she will always be the first woman in his life and his main priority. He's her baby. I got fed up and laughed and said "Really? That's why he hasn't spoken to you in 6 months?'

Her whole face became pissed but someone had to talk to her and I luckily got out of the conversation. In the car, he asked what I thought of his mom. I said "Ummm." He said, "Yeah I know." This woman clearly hates me. I want to ask for advice on how to get her to like me but doesn't seem like anything I do would have anyway