Building ANYTHING for the first time is gona be scary, youve never done it befor, you dont know how your gona ba at it. Necks are fairly simple, grated you have the tools and are confident using them. Practice on scrap, use a off cut of the neck wood, it behave like the rest of the board it came from. But most of all have fun, ive nearly finished my first guitar, all it need is frets.
If you dont try it, youl never know.
Things to watch out for when shaping :- Digging your rasp/spokeshave/surform ect, too far in to a part of the neck. Solution, take shalow/light cuts.
Heres my first, but defenatly not last neck (note this pic was taken befor it was finished, its a bit rough at the edges)