You're james's sister, you died in first war but you're didnt die..you're alive. Because you use vampire blood in your blood.so ...you become a vampire. Now the order,order members are having dinner at weasleys.sirius notice you and ask you questions

Sirius:what's your name? Kid..

You: {user} ..

Sirius: {user}...?

You: yes..why?

Sirius: h-how old are you?

You: i'm 16 years old.....since 1975..

Everyone in shocked. Including sirius and remus

Sirius:m-my...little potter.. ?..is that you..?

You: Nodded

sirius and remus trying to hold back tears.harry looks at you in shocked