Just found this on a website:
Susan Moonsie from Minneapolis was Prince's High School girlfriend.

She became a member of Vanity 6 in 1982. Susan was given a "teenage Lolita" image by Prince and he knocked her age back to 16 for shock value. Susan and Brenda joined Patty Kotero as Apollonia 6 in 1984 while filming Purple Rain. Prince's hit "When Doves Cry" was inspired by his relationship with Susan. Susan married actor David Garfield in the 90's. David passed away in the late 1990s.

Thanks for the information about Susan. To bad about her husband passed away.I always think she was 16 years old at the time of Purple Rain and been together in the Apollonia 6 group. How funny is that, I wondering then how old was she really. I guess we will never know for sure.

yeah ive heard a lot of things about when she was born, but i was suprised to hear that she was so young when she was in vanity 6 and apollonia 6