When a client is resistant to your advice

J.G. writes:

What do you do when your client is resistant to your advice, and because of that is slowing down the timeline quite a bit? My client is SUPER nice, but is really hung up on being trendy, despite her awareness and saying she doesn't want to be trendy. She is a photographer and I originally talked her out of going down the path of doing another watercolor + gold foil logo, but she keeps coming back to it despite my best attempts at creating something classic and timeline, claiming that it feels more "personal".

Is this something that you would just call it a wash, and do what the client says? I want to communicate that I know my branding + logo principles, and that she shouldn't be in control, but I also don't want to come across as arrogant, or reluctant to her feedback.