Is it normal for my sister to come to me for everything?

My little sister almost always comes to me instead of our parents whenever she needs something. If she needs to be driven somewhere, needs help with something, or even has a health issue to discuss, she'll come to me with it. She doesn't want to deal with our parents much, and I can't get her to say that anything specific has caused this apparent lack of trust. In my experience, they could be distant sometimes, but usually willing to at least help when asked. I'm not sure if there's something between them and her that I don't know about. She only turns to them for things requiring a legal guardian and mostly wants them out of the picture as much as possible, preferring me to be involved instead. I don't really have a problem with it, she's a nice person and I kind of like being there for someone, and I'd rather be able to spend time with her than lose out on a close relationship. She has no obvious psychological issues or anything. But I'm wondering if this is indicative of problems that I haven't been able to find out about.