Just found out my co-writer for a long slash fic project is 17. What do I do?

I am a big fan of co-writing writing partnerships. However I had a new situation recently that I’m none too happy about. There was a very talented writer who happened to post that they were looking for a partner to co-write fics. I’ve actually been a fan of their work for a while, and dmed them to collaborate, linking a few fics I was proud of as work samples. We started sharing writing snippets back and forth, and eventually started co-writing a fic together. Then, today they told me they were 17.

I had no idea based on the level and content of their writing and blog, and am shocked. We were writing a slash fic, which means there was explicit content between men in the fic. I just assumed they would be over 18, it didn’t occur to me that a minor would be writing things like that, and had been creating for quite some time too, longer than me, who is a newbie by comparison I wish they had told me when we first made contact or listed it somewhere on their blog. Should I end the working relationship, and thereby the fic? The fic had a lot of readers and commenters, and was a project close to my heart, so I’m just generally unhappy right now.

They told me it doesn’t matter because we are not hitting on each other or having a personal friendship, just having a working relationship like coworkers or collaborators. But I’m not sure. I’m new to fandoms and online interactions myself. I’m in my 20’s and had kind of been living under an online rock prior to being inspired by fic and starting to write. I don’t like to chat, just to focus on the work. But I’m unhappy that they didn’t tell me that they were 17 earlier and mourning the possible loss of my fic. Is there any truth to what they’re saying that it’s okay to work on a slash fic together if we keep things strictly business?

I know adults are supposed to set the boundaries but I am trying to decide what boundary would be the best and most balanced to set here. I know we would both be upset to scrap the fic. I’m just so bummed out because this fic was the first time I felt motivated to create in many years, and I wish things didn’t go the way they did. They’re telling me I that it’s a professional working relationship, since we talk very technically, about writing. When I was in hs I did take creative writing classes and talk about some mature scenes with my teachers from a technical point, not in a creepy way, and it did make my writing better. And I read books in English class that had sex scenes in it. At the same time I don’t know what’s typically done in fandom for situations like these. i want to consult everyone here as how best to proceed. I was looking forward to finishing the fic together and it brought me a lot of happiness over a period of time, but feel like a wrench has been thrown into the situation. Is this a situation where I should even consider deleting the fic? Thank you.

Edit: I have received advice saying it might be okay to ask them to pause and resume after their bday. should I also ask if they would be okay with collaborating on safe-for-work content before they turn 18?

Edit: thank you to those of you who commented. I’m going to sleep on it and come back. In the meantime I would be thankful for more perspectives bc I honestly have no idea.