On her card the weapon box is not checked. Does this mean she takes penalties when she uses a weapon?
It means she might take a penalty, or that she might not have access to all the weapon's powers, or that the weapon will act differently. It will vary from weapon to weapon, and some weapons don't care. The weapon's power will tell you if/what difference being proficient means for that weapon.
There are some weapons that say "If you are not proficient with Weapons, the difficulty of the check is increased by 4." So if she played that weapon for a combat check 13, for her it becomes a combat 17.
There are some weapons (the bows mostly) that say "If you are proficient with weapons, you may discard this card at add 1d4 to a combat check at another location." So Merisiel can't use that power.
This image of the Longbow from the Ranger class deck shows both those things.
For guns, being proficient with weapons tends to mean that you are less likely to have the shuffle the weapon instead of just revealing it, like on this Blunderbuss.
And for some weapons, being proficient makes no difference whatsoever. Like this Main-Gauche.
Thank you for clarifying this for me.
Thank you for clarifying this for me.
You are welcome. Good luck on your adventure.