One of the best ways to preach Christ to others is through your own life.
If people see something "different" in you, they may say "I want what he has".
We're just ambassadors handing out invitations to Heaven.
Now then we are ambassadors for Christ, as though God did beseech you by us: we pray you in Christ's stead, be ye reconciled to God.
- 2 Corinthians 5:20 (KJV)
To make it clear, the NIV translates this as "as though God were making his appeal through us".
If you're all broken inside, but have Christ within you, it can be a very powerful testimony.
The sacrifices of God are a broken spirit: a broken and a contrite heart, O God, thou wilt not despise.
- Psalm 51:17 (KJV)
You can start testifying at any stage.
Just like with the demon possessed man who was put into the ministry straight away after his conversion.
And when he was come into the ship, he that had been possessed with the devil prayed him that he might be with him. Howbeit Jesus suffered him not, but saith unto him, Go home to thy friends, and tell them how great things the Lord hath done for thee, and hath had compassion on thee. And he departed, and began to publish in Decapolis how great things Jesus had done for him: and all men did marvel.
- Mark 5:18-20 (KJV)
If it's in your heart to share Jesus, don't wait for anyone.