Can you critique the first paragraph of my story in the making?

Moor abruptly spewed the ocean water from his throat, sending himself into a series of violent sneezes. They overtook his body, and he shook like an earthquake.br
"Whoa!", Ima yelped, regaining her balance on the saddle.br
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"This isnt good water, Moor. Didnt it smell odd to you?", asked Ima, as if he could comprehend. From north of the docks, the water's ripples grew wild and large. Moor's attention was not to the cluster of steam-driven ships approaching. Ima came to realize it too. They were here, at last. Her heart skipped, tripped, and plummeted into her stomach, or so it felt.br
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--- Is there anything to be added? What inferences can you make from this, alone? Can you tell she's riding a triceratops and is about 9? I didnt want to reveal those things until later in the next chapters. Should I have added an adjective to describe "ocean water"? Should I have described "shook like an earthquake" better? Like "shook like [insert imaginry volcano here] in [insert year]? As you can tell, I havent finished plotting.