Shouldn't jump the gun without knowing her reasons.
Anything could've happened between the time she said she's going to study and when you saw pics she posted.
But you already expressed yourself. You might of been right, she lied, and no need to give time to such people. Or... she didn't lie at that time.
Could be several other things also; she didn't like the time she spent with you, she's not into drugs, she's not into suicidal people, you just didn't do it for her (sexually)
It's her right to say; no.
And your right to say what you did