What is the interpretation of a non-smoker dreaming of smoking cigarettes with thick, white smoke that quickly disappears, after performing Istikhara prayer concerning an immature suitor?

You should inquire about the suitor from trustworthy individuals to ascertain his religious commitment and character. If he possesses both, then marry him, for the Prophet, peace and blessings be upon him, said: "If there comes to you one whose character and religious commitment you approve, then marry him. If you do not do so, there will be turmoil on earth and widespread corruption." And Al-Hasan (definition) Al-Basri said: "Marry her to a man who fears God, for if he loves her, he will honor her, and if he dislikes her, he will not wrong her." Seek guidance from God through Istikhara repeatedly. What you see in a dream does not necessarily have a connection to Istikhara. The preponderant view is that one should proceed with their matter after performing Istikhara.