I'm not judging her heart; God will do that. It's very sad situation and I can empathize with her plight and even understand her decision if she is not a Christian which I expect she is not.
What unbelievers fail to grasp (and even many Christians), is that in the context of Biblical teaching, this life will be difficult; and that God allows these devastating trials and tribulations for our good, for our sanctification - refinement by fire so to speak.
I believe God allows special grace and peace to those who believe and trust in Him fully while in the deepest of valleys, particularly imminent death. How else can one explain second century saints singing hymns while being burned at the stake, or calmly being mauled to death by wild beasts in the Roman coliseums.
Lastly, taking ones life, God-given, purposely is suicide regardless of the semantics the law tags it with and the circumstances involved. Suicide is self-murder, Which I believe is morally wrong and a sin. Not an unforgivable sin but a sin nevertheless.
Furthermore, assuming she is an unbeliever, this life is all there is before an eternity of judgement. And she at her young age is intent on giving up days, or weeks (?) of her very short life wherein she might find the God who is ever ready to answer and grant her that peace, grace, and very much more.
