Trex 600 is a great heli to start with. You've already gotten great advice on electric vs. nitro and it seems you've made your mind up on that so I don't have anything to add.

Flying a CP heli like the Trex 600 is going to be VERY VERY different from the CX. Coaxial helis like the CX practically fly themselves, CP helis are inherently unstable. To get an idea what it's like flying a CP heli, imagine holding a square piece of glass horizontally and trying to keep a marble in the middle of it.

If you haven't already, investing in a flight simulator like Great Planes Real Flight is a good idea.

They are fairly complicated to setup. Nice thing about Align is they have better manuals than the cheap clones. But you'll definitely want to get help from an experienced pilot. Also look for finless bobs trex setup videos. I think they're mostly for the 450 but the principles are the same.

To learn how to fly, look up Radds School of Rotary Flight. It will get you in the air with the minimum amount of crashes. Oh ya, you WILL crash