Your mom is right about Chapel Hill being a top school. And it is more affordable than Auburn. You seem to have a strong emotional pull toward Auburn and that is important too. If you were my son I would urge you to consider Chapel Hill too, but in the end leave it up to you. Sounds like your mom is doing the same.
Any chance you could visit Chapel Hill to reassess?
I think it would benefit you to really figure out why you want Auburn so much and if it is clear to you maybe you can make it clear to her.
Chapel Hill is a well-known excellent public and a lot of parents would want it!