The drywall part is easy. Deconstructing the brick without having a damaged mess left is the hard part, and not something I would recommend for a newbie. You may be able to get the top two rows of bricks off without much inadvertent damage, but those triangular projections can't be removed unless you take off all the fireplace brick, all the way across, down to the bottom of the triangles. If you don't understand why, that's even more reason for you to not attempt this yourself. If you're really serious about this, have a brick mason look at it and explain what's possible.

We just removed our brick fireplace and the drywall looks good. It still has the original texture but we will have to clean off some areas where the morter stuck.

The problem for you is going to be those brick corbels. They are probally suported with bricks turned 90 degrees for support in which case you would have to remove all the brick down to their bottom level and then reinstall brick to the height you want.

If you look closely under the corbels you should be able to tell. Personally I kind of like your fireplace:)

I think it’s awesome as is. Very cool design.

How old is the house? What look are you going for?