Question:Is this normal?

It's been a long time since I've gotten a tattoo, and I was wanting to get a watercolor piece about 8 inches long. I've been talking with a guy who came highly recommended, but other than pulling a few photos off Google, he is telling me that he won't be able to do a mock up. That I just have to trust him that it will turn out good and what I wanted. Is this normal? I've never been to a tattoo artist who's done this, but I also haven't gotten a lot of tattoos.

Any advice is appreciated!