My dog has a bald spot by hear ear?

My dog is a shetland sheepdog, just about 7 years old, and she has a bald spot by her ear and she's been itching it. it's not noticable unless you pull some hair away. We just found out about this a couple days ago. It just looks like it's bald, it doesn't have scabs or flakes or anything, and no red ring, from what we could see. I'm getting worried and my mom is getting mad at me for it so I don't know if she'll be able to go to the vet. She's inside for the most part, however, she can go outside in a dog kennel but that's it, other than doing her business and going on walks. She's very, very healthy, she hasn't been exposed to mange, but could it still be that? I am getting very worried and I don't know what to do because my mom gets mad if I say that we should call or take her to the vet! What does it sound like? Thanks!