You can perform loops perfectly fine in Normal mode. But when performing flips you'll loose a lot of altitude (which can be very dangerous). Rolls can also be performed in Normal mode, but if you're gonna try, you better have some good roll rate on that bird. I would not attempt rolls in Normal mode...
There can be a huge difference flying Sim compared to your real bird, as there are many settings to consider. I would advise to be 110% comfortable in Normal mode, with all the standard orientations, banked turns and fast forward flight before you try any acrobatics.
And when you come to the point where you want to do some stunts, you should start using IdleUp mode.