Need help from anyone who knows about hacking data? (Friendship, App, Facebook)

I made a big mistake. I was on Snapchat and someone asked me who she was. It turned out she was a girl or a young woman. She wanted to know what I looked like so I sent her a snap. I asked her too and she sent one which looked completely normal. Then she asked me if we could talk dirty, I wasn’t really opposed to it and said yes. After a bit of texting she asked if we wanted to exchange pictures. At first I told her to send first, which she ignored for 20 minutes, so I started. When she opened it, it wasn’t long before there was a picture with my face on it, the nude picture I sent her, my Snapchat account and my Instagram account, which she somehow found out. It also said that I’m a child molester. She sent a screenshot of all the accounts I follow on Instagram because I stupidly wasn’t on private. She then demanded that if I didn’t send her $300, she would send the picture to everyone I followed on Instagram. I panicked, of course. Then she sent me the first screenshots of her sending the picture. I called these people to see if they had received a picture. They all said no. She probably sent it and deleted it straight away. The time when the picture was sent was 7:00 a.m. and mine was around 2:30 p.m., which is why I assume she was writing from the USA. She kept threatening me and I didn’t write back. That evening I reported her on Snapchat and her account was deleted. It’s now been a day since she was removed. I’m worried that she’ll send it or message me again on Instagram. My Instagram profile is now private again and in the chat I said I’m 16. Does anyone have any tips on what I could do or what you think could happen.