There are some folks who are going to say you can't get a decent mtb for less than $1000, but I'm not one of them.

That should be a decent bike to learn your mtb skills with. Nice that it has disc brakes at that price.

Go for it, and after you've been riding singletrack for a year re-evaluate your needs. If you've progressed enough that you're craving more of a bike, sell off the Giant and start shopping again.

Steve Z