She's mentally an adult. At this point, her naivety and stupidity are inexcusable. She's a damn cretin.
Also, do the skills really come from Garland, or not? Because if they do, then literally all of this is his fault. Imagine creating a unique skill that lets people steal/swap skills. (Actually, Charlotte's skill which allows her to change people's statuses is ridiculous as well. Thankfully, she at least uses it for good.)