If i make a house will people be able to ruin it by doing something like taking my blocks or placing there blocks all over the house or exploding the house?
Also will i be able to build with other people
Is minecraft ps3 edition safe from greifers?
Nah, sorry kid, there's definitely a possibility of players griefing, blowing your creations up with creepers, TNT, etc. But it all depends on which server you play on. Some have rules and regulations that prevents players from touching any of your creations and others don't. Yeah, you'll definitely be able to build with other people. It's an awesome game and it's definitely worth getting.
Since you can't use a plugin to control what can and can't be destroyed, griefing is definitely a possibility. If you can, make a backup of the world before you bring it online with other people so you don't lose anything. If you have to go AFK, temporarily take down the world so they don't destroy things while you're gone. Most of all, be careful who you play with.
You will be able to build with other people. Keep in mind that if you're in survival, a player will have to gather materials.