Crashes way too much

I would give 5 stars if the game did not crash! Whenever I load an infinite world or for just no reason at all, IT CRASHES :( Please fix this!
And also I think its dumb how the world either crashes or is super small! I want to do survival but I get like no space to build my house! But of course I could go to the huge world with space and CRASHES! Please fix that! :(

Ninjaiden about Minecraft: Pocket Edition, v1.1.5