I don't want to lose my data on my iPhone, can someone help?

I got an iPhone 4S not too long ago, maybe a month or so. I already have it set up and I bought all of my music on iTunes. I am getting a MacBook Pro soon, and I want to load the music I have on my phone onto the MacBook without deleting all of my data on my phone. Is this possible? It would be really helpful.

Just open iTunes, sign into the store, and you can download purchases directly from the store from your new Mac. No need to plug the phone into the computer and no risk of erasing your phone.

So long as you are using the same Apple ID on your Mac as you are using on your phone then anything you purchase through iTunes will be available on both devices. You can administer your Apple ID at https://appleid.apple.com/