You sound young, I'm assuming you are. My real name is Faith so I was raised as a Christian and have attended church my entire 48 years.
Church is not a place of perfect people, quite the opposite actually. So the people that say everyone at church should accept you and be kind just because you are at church is not true. Everyone, I repeat, EVERYONE, has their own personal issues. Not everyone is accepting and friendly to every single person they see.
I have experienced this myself just recently this year, after leaving our church, attending another, then going back, I realized not everyone is going to be my friend. And that's ok. I know it's harder to see someone treating you badly at church, but that's on them, not on you.
So if you are attending church for the sole purpose of making and keeping friends, then you should not be going. You go to church to learn and serve and make disciples of others.
If this is your only problem with this church then I would not leave, I would just ignore her. For whatever reason she doesn't care for you and she's making that obvious. But that is HER issue to deal with, not yours.
I used to smile, say HI and wave to everyone, that is my personality. But I started to notice that if I made eye contact with some from across the room and would acknowledge them some of them would just look away. It was obvious. So then I realized it was ok to just be friends with people that like me and care about me. I don't put any effort into those people anymore or make the "first move". I now will walk right by them. If I happen to cross paths, I will be nice, but not otherwise. And that's ok. For whatever reason these people don't care about me. I'm very active at church and have a small handful of close friends there and more casual friends and some I flat out don't care about. No biggie. It's not why I'm there.
I hope this helps you and you take it to heart. Don't give up on a church just because someone treats you badly. It's not the reason you are there. Just let it go and be happy with the people there that love and care about you and let the rest go. Good luck.