I feel I'm on the edge of life
What caused this realization?
It's I don't know what to do with my life
I wouldn't worry too much about that.  It can feel hard at times, but life is a journey without any real destination.
What if I'm suicidal and shouldn't decide that by myself.
In that case, then you should definitely seek help from one a therapist or a hotline.  They can let you talk about whatever has made you feel like you don't want to go on, and you will be able to understand how to move forward.