My question involves criminal law for the state of: California

Hey guys,
I am a 23 year old male and I am currently a university student. I am a good kid with a clean past and am a model citizen. Two months ago, however I ran into a problem and it has just been bothering me and making me insane. I don't know if it is a legitimate worry or if I am just being paranoid.

For about 1 year from January 2017- January 2018 I used an anonymous encrypted international chatting app to talk to people cleanly on. This app was only for those who are 17+ and I used it thinking that I could make friends on it to talk to. I made countless numbers of friends both male and female, ranging anywhere from 17-60 and we had clean normal chats. You may be wondering why I used this app and the reason is that I have severe social anxiety and have trouble talking to people so I use this app to help me out and give me a sense that I have some sort of social life. Well, in January of this year I entered a chat and of course at the start I asked the age of the lady I was chatting with and she said she was 17. I chatted with her cleanly like I always do. I asked her normal things like I always do like "how is it going", "do you have any plans today", etc. Also, to verify that I talk to a real person I ask for a normal clean picture. I always send a picture as well, and it is simply a fully clothed picture of myself with my face blurred to keep my identity concealed. This person sent a clean picture of themselves and and then proceeded without me even asking to send me a nude picture. I was shocked and never even asked for one and I immediately deleted the chat. I am sitting here two months later and am very worried. I even ended up leaving the app due to this experience and this has caused me to become lonely as well because I relied on chatting with people on this app cleanly for moral support. I never joined this app for this disgusting and pathetic purpose. I did it to talk to people and now incident has been driving me nuts, because I never even did anything wrong.

I am being serious about everything I have said and would really appreciate advice. Do you guys think I have anything to worry about?