From my point of view,it's not a good choice to build a gunpla such as unicorn or sazabi(though they are extremely cool),especially when you are a beginner .
Start with easy ones (like RX-78-2 or ZAKU,etc)will more easily bring you a sense of achievement .
Or you might soon lost your interest in building gunplas if you have difficulties in building a cool but more finicky one.
Maybe you can heat the plastic a bit so that you will be easy to make it straight again.
Well,so it is. You need to paint after you build it because the color of FG is white（only white）. :-）
I think the most easy grade to build is FG