Fiberglass is pretty easy to use. Gelcoat is also easy to work with, especially if it's white. If you gotta match the color, it can be difficult.
Here's some work that i did, absolutely zero experience.
BEFORE
After
Can't tell there was an damage, and strong. Done for about $25 and a few hours work (mostly sanding). It all can be done with normal gargae tools, and some stuff from west marine. A couple screw holes can't be to bad.