New Iphone 4. Creating new account or not

I am getting an Iphone this week.  I have had an Itunes store account, that is shared with my kids, for several years.  If I start a new account on my laptop only, will I lose all my purchased music and apps?  The kids have access to all of the music and apps on the family computer.  PLEASE HELP!     My main concern is the imessaging feature and other things that share info accross all devices.