Hi, when I read "it's a coffee shop" it didn't sound completely unfamiliar to me. Then I remembered that it maybe it's a feature of some dialects, or maybe it's not but there are some people who talk that way. In other words, I think I heard that some people use "it's" instead of "there's". It's not correct from a prescriptive point of view, obvioulsy, and it's not very common either, I think