If you're new and are interested in learning the basics first, then gimp would be a fine choice. It's free and easy to learn. With that said, Photoshop is by far superior in just about all aspects.
Personally, I generally recommend to just test the waters and learn the basics on gimp. If you end up losing interest in graphic designing later, then you won't feel as bad since it was free. On the other hand, if you end up really liking it then you could upgrade to PS.