Darker areas on daughters neck

[Fcx20]

Hi, totally random..

However, my child is 3/4 white and 1/4 Black Jamaican. She is pale skin with blue eyes but has olive tones to her sometimes. I notice around her neck she is much darker and the creases are white, I'm just wondering if anyone else has noticed this on their child? I'm not concerned of course but I'm just curious because it becomes very obvious on her at times. She is 16 months old so Im not sure if her complexion will get any darker or the darker rings around her neck means she'll devolop more melanin but the texture is how it should be and when ive read Google post it says it could be a condition but they mention it would be leathery but hers isn't. Thanks in advance