I am eloping in my church and inviting only a couple of people, is this still eloping?

That's a small intimate wedding rather than eloping but so what, what you call it doesn't matter you do what ever and invite who ever you want. Just because it's in a church does not mean you have to make a big deal out of it. Just tell your mother that you are doing things this way and that you will miss her if she doesn't come but you do understand. She can't argue with that and hopefully she will grow up enough to see sense. I hope you have a wonderful day.