Again, and I can't stress this enough, you are not only not an adult at 18, you're not even close.
Your judgement is definitively unsound. You're brain has yet to fully mature and with that immature state comes compromised judgment, logic, and impulse faculties.

You are especially vulnerable to manipulation at that stage of life, as not only are you immature neurologically speaking, your brain is also under hormonal assault, making things even more tempestuous.

You can't know how you'd have reacted, you can't hypothesize about this. That girl went through it. You did not.

Have some goddamn compassion.