The most powerful thing you own is not an argument. It is a testimony — and nobody can debate what happened to you.
In John 9, a man healed of blindness is interrogated by experts. He cannot answer their theological questions. So he says: "One thing I know, that though I was blind, now I see."
That ended the discussion. Yours can too.
Your story in three parts
Before. What life was like — the ache, the emptiness, the thing you were chasing. Be honest, not dramatic. "I looked fine and felt lost" is a story many people need to hear.
How. What happened. Who said something. What you understood. What you did about it.
Since. What is different now. Not "everything is perfect" — that is not true and people can smell it. Something more like "I still struggle with X, but I am not carrying it alone any more."
Keep it short
Practise until you can tell it in two minutes. Most opportunities are short. A story you can actually tell beats an eloquent one you never finish.
You do not need a dramatic testimony
Growing up safe and coming to Jesus quietly is a wonderful story. It says God's grace can reach a life before it breaks. Do not apologise for it.