I don't follow Steven Universe stuffs religiously, but I remember that I was looking forward for an Emerald and even made a sketch for her potential design. Now that I've seen her official design, I'm still disappointed that she isn't as short/young as Ruby and Sapphire like I always envisioned. But I wonder if she has some sort of mind power or perhaps geokinesis.
hmm.. I’m not sure if you’ve followed enough to know who Aquamarine is but she is a type of Beryl, like Emerald. Aquamarine is pretty small so we all assumed that Emerald would be too.
I also think we thought Emeralds would be small because of the associations that Ruby, Sapphire and Emerald hold in society. They are usually are paired together, it was just natural to make that assumption. Take the Pokémon Games for example.
I, for one, love that the crew did not take the small route because it would honestly just be a show of little gems and how boring is that. I love when they prove us wrong.
With that being said, I hope you learn to like Emerald because personally it was love at first sight for me!