U will be ok
Like everything else in life there is a first time for everything..experience comes through learning so u have to have an open mind yes there might be mistakes but u learn and move on...go in with a positive attitude.
There are also a lot of resources to be found online...google is ur best friend.Magazines like maximum pc and Pc World are good too...oh and lastly u might want to pick up a copy of ''Upgrading and Repairing PC's.
Good luck bro... i know u will be ok
MSI NF750-G55 Motherboard , AMD Athlon II X3 445 Rana 3.1 GHz ,
Corsair XMS3 4GB 2 X 2 GB PC3-10666 ,Seagate Barracuda 500 gb HDD , Nvidia GT520 , Acer 20'' LCD Monitor