If anyone happens to be interested, I found it and the name is BL Metamorphosis, but it is not on the website ;-;
i was interested
It is really good! One of my fujoshi friends also thought the concept was very interesting and bought the first 2 volumes. She let me borrow it and it was so good. I will definitely buy myself a copy and if you can, try it out as well. There are 3 volumes currently, just saying
also if you are interested "My son is probably gay" is very good. It is just something to read if you want a "bl" from the mom's perspective
I don't know if it is here, but I saw it somewhere once. It was about this high school girl who was a fujoshi and she met this grandma at a library. They start hanging out and the grandma also came to love bls as well. This was based on the description I read some time ago, so it might not be 100% accurate, but I you find it or any similar titles please send it to me ^^