The book's MC was named Ren I think. He was 18 but looked 12 cause his parents used him as testing for a bunch of drugs. He basically lives in the hospital now. In the world he's in, a full dive VR game was just released, and the company is giving out 5 OP classes to people with sad and horrible upbringings. The 4 others faked their story mostly, bit Ren's was true( Being the MC, he got a spot). He was the last one to chose his class and got the supposed worst one. I think it was a crafting class. He was friendly with the NPC's. If it's not on this website, then it is on Scribblehub.

https://www.royalroad.com/fiction/544/master-of-all-jack-of-none

Easily found on a search for "Ren" under the virtual reality tag. It's one of the more popular litRPGs, but I usually skip over anything with the harem tag. 

Thank you.