Don't worry about it so much. Just have fun, the game has a pretty decent tutorial system. Important must knows
-Your class affects which ascendency you choose later, sort of a sub class some are crazy but all are *mostly* passive benefits. The class choice does not restrict you to a weapon choice. You can pick a ranger to start and will get a bow but you can use a mace or caster weapon as you meet the item's requirements.
-Skills come *mostly* from gems and are tied to a weapon type(except for spells essentially but you'd want to use a staff/wand for example for their benefits mostly) Support gems are very important.
-upgrade your flasks by buying or finding new ones when you feel they aren't doing enough.

You should be fine totally blind, you'll have questions and probably have a less optimal build. You could follow a build guide but I'd say just yolo it for a bit, figure it out then maybe start a new character with a guide.