Dreaming of a loved one, especially someone like your grandmother who has passed away, can be quite emotional and significant. In your dream, the transformation of your grandma getting younger may symbolize a desire to reconnect with memories of her from a time when she was healthy and vibrant. It could reflect your feelings about her life and the impact she had on you.

The changing of her hair could represent the different phases of her life or the various roles she played in your life and the lives of others. Since you didn't find it strange in the dream, it might indicate a sense of acceptance or comfort with the concept of aging and the passage of time.

Overall, this dream may suggest a yearning for comfort, guidance, or wisdom that you associate with your grandmother, as well as a celebration of her life. Reflect on your feelings about your grandmother and the memories you cherish. It might be a good time to honor her legacy in your waking life.