Why is my world not unlimited?

Strangely I can see all my world with its very limited resouces. I can't get past the edge. I bought it only last night (23/4/15) so isn't it supposed to be unlimited? It's mostly water with some various biome islands... spruce trees on most, one with oak & beech. How can I play in such a tiny world? I've made about 5 different worlds, & all are like that, some more watery than others. All small in area. A couple of sheep, maybe a cow, no chickens or pigs so far. Does it improve with time?
Best Answer
Since version 0.9.0, Minecraft: Pocket Edition allows infinite worlds, but classic 256 by 256 worlds are still supported as a separate world type.
While creating a world, look for an Advanced button, and select Infinite world type in Advanced options.
Pictures about "Why is my world not unlimited?"



Is a Minecraft world truly infinite?
Minecraft's world generation isn't infinite, but it does create enough physical blocks for players to interact with that they would never run out of feasible room to craft, build, dig, and mine to their heart's content.How do you make an infinite world in Minecraft?
Horizontal limitsThe world border is located at X/Z \xb129,999,984. Chunks still generate past this point, but the player cannot go past \xb130 million blocks out.Do Minecraft worlds have a limit?
Converting to infinite To convert an Old world to an Infinite type, select the pencil icon next to the old world in the world selection screen, then select "Make Infinite!". This creates a new world with all of the saved data (inventory, terrain, structures, etc.)The $250,000 Unlimited Flight Pass: A Terrible Mistake
More answers regarding why is my world not unlimited?
Answer 2
In the latest version of minecraft you can edit your worlds and make them infinite.
Just press the edit button next to the world, and Press the "make infinite" button.
Sources: Stack Exchange - This article follows the attribution requirements of Stack Exchange and is licensed under CC BY-SA 3.0.
Images: Pixabay, Porapak Apichodilok, Pixabay, Andrea Piacquadio