This is what the Bible says:

John 10:27-29 – My sheep listen to my voice; I know them, and they follow me. I give them eternal life, and they shall never perish; no one will snatch them out of my hand. My Father, who has given them to me, is greater than all; no one can snatch them out of my Father’s hand.

Suicide is wrong because it is taking a life made in the image of God (your own). But people don’t lose their salvation because they sin, whether it is taking a life or telling a lie. So whether or not she went to heaven or not is the same criteria for all of us: had she truly believed in Jesus as Lord and confessed Him as her Savior?

Suicide is a very delicate and painful subject for those who have lost loved ones in this way.