Here's some advice:
If you want it realistic, try making the beach bigger, because I'm pretty sure a ship wouldn't land on an island that's smaller than the ship itself and only has a tree and 3 flowers
Also, why is there only one tree on the island? And why is that tree taller than the ship?
One final thing, the default tree isn't suited for a build like this, try making some custom mini trees out of bricks.