Is consuming media a crime?

Hello, this may be a long and extremely strange one but please bear with me. My friend has struggled with OCD for a long time. She’s recently disclosed to me that for 3 entire years she’s been unable to move past the thought she will go to prison for something she did at 18. I am of course worried for her and ask her to explain.

When she was 18 years old she read a fanfiction on a popular fanfiction website. The fan fiction was related to the The Last Of Us. If you aren’t familiar it’s a kind of apocalyptic world where a man and a 16 year old girl (both fictional and not related) basically are trying to survive these zombie type creatures. In this fanfiction it’s written as though Ellie (16) is romantically and sexually involved with Joel (adult man). My friend read this at 18 (literally just turned 18) and is convinced that it was illegal to read this media because of the age gap and it being a story of a sexual nature and the age of consent. It has no other themes it’s just a short story about there relationship. She’s convinced because it was set in America and a state where the age of consent it 18 that is makes her some form of ped0phile that has committed a crime with being 18 at the time.

I have tried to explain there is plenty of media out there ‘Lolita’, “I spit on your grave”, “a clockwork orange” they portray some really messed up and illegal stuff and that doesn’t mean anything about the person consuming that media let alone mean a crime has been committed. She is convinced tv and film go through some form of system to be distributed and that makes it okay but fanfictions are posted by anyone so don’t pass this “system”.

Shes not looking forward to anything in life because she doesn’t see a future that doesn’t involve a jail cell, she thinks she will lose everything and be tarnished an abuser.

I have 2 children and she’s been avoiding telling me in case I thought she was a risk to them! Shes been sad anytime I’ve ever done anything nice for her thinking I would think she’s a monster if I found out. She does have other things such as health OCD but it’s this fanfic one that is HUGELY eating away at her life at present. I too have OCD and have had obsessions, compulsions and rumination and I’ve come out the other side with years of therapy and medication but even with similar experience she’s not hearing me and being able to move past it she said the only way she can move past it is if she hears a lawyer or a police officer say she’s not committed a crime but she point blank refuses to talk to anyone herself.

So just to clarify her main issues if anyone can help me reassure her
-characters are 16 years and an adult
-she was 18 at the time of reading
-it is a fanfic of fictional characters in a fiction time
-there’s no photos, no graphics, just text
-it’s published on a fanfiction site by a random person
-she’s concerned 16 is below the age of consent where it’s set
-friend lives in the UK if that’s remotely relevant

If anyone at all can comment and help me show her from a legal standpoint that she has not committed a crime remotely I would be so so so appreciative. It’s ruining her life and I don’t know how else to support her. We are seeking a medication appointment on Monday and I’m going to suggest therapy again when I next see her in person but I would love to have comments from people that can help reassure her.

If you’ve read all of this thank you so much, sorry it’s a strange one I just don’t know what else to do.