I remember one night my son was over an hour late. My normal feelings would have been fear and worry. But as I prayed, God calmed me down and gave me His peace. Don't use Christian Jargon that non-Christians will not understand. Life is not always wonderful, totally fulfilling and without problems.
People appreciate accuracy and realism.
Don't mention the names of denominations or church groups. Keep your conversation positive and focused on what God has done in your life. When telling your testimony, be as specific as possible, humorous if appropriate, and very clear when explaining how you invited Christ into your life. You should write out and memorize your own three-minute testimony. Practice delivering it conversationally, perhaps with a friend.