Exhibit A: "he was kinda only there for the drama in a way, I didn't see the red flags while in the situation. He was manipulative, dismissive, threw around slurs in the same sentences while talking about serious mental health topics, claimed he helped "multiple people" through things like this (he's 15) and acted like he knew everything kinda."

Exhibit B: "I'm 18 and Noah is 21"

I'm not really sure what to write at this point. My reaction to Exhibit A is that your situation with Noah reminds me of a time when my empathic teenage daughter was "emotionally hijacked" by an attention-seeking boy three or four years younger. He was insinuating all sorts of unhealthy behaviors. Finally she asked me for advice (even after he said not to tell anyone else). I considered his story and noticed an obvious lie and concluded that he was getting a thrill from twanging her empathy strings. We got the social worker involved the following day and the issue was resolved. (He was a special needs student under the social worker's care.)

All you know about Noah is what he tells you. He could be anyone, any age -- 15, 21.... 39. Could even be AI programmed by a bored computer science major on summer break!

If you really are "carrying a lot of guilt about the situation," I hope you will stop and forgive yourself. Suppose this happened to a dear friend instead of you; what would you tell her?

Mental health professionals are trained to somehow maintain a barrier between themselves and their patients to prevent getting "sucked in." Please protect yourself in a similar way.