In short, Aziraphale gave up on heaven as soon as he arrived, I think he preferred something and blah blah blah... we all know the real reason. But you were a little sad after all you had finally found something that loved Books. But Aziraphale was very kind to let you continue working for him in the library, whenever you had some time you would incarnate in the library and help him organize the books and even learned to read several of them, Aziraphale became almost a father figure to you, teaching you everything about the earth like how to drink tea... tea the person who discovered it must be in heaven and you definitely wanted to talk to him

in short, you discovered that technically you were an eternal teenager on Earth, which wasn't bad after all, you adopted Aziraphale and Crowley as your parents, even though Crow didn't like the idea.