“…but to think soberly, according as God hath dealt to every man the measure of faith.”
Romans‬ ‭12‬:‭3‬

You had enough faith required to change your nature and state; from an unbeliever who is alienated from God to a child of (and an expression of the righteousness of) the living God:
“Beloved, now are we the sons of God…” 1 John‬ ‭3‬:‭2‬ ‭
“For he hath made him to be sin for us, who knew no sin; that we might be made the righteousness of God in him.” 2 Corinthians‬ ‭5‬:‭21‬
If you can believe that God sent his son just for you, then realize that you can believe all the things that came with that transaction and your new birth.
You already have a prerequisite requirement of faith that can grow. The solution to whatever doubt you might be experiencing is hearing more words, and the beautiful reality is that you are born of the word of God, so he is not asking you to grow your faith with a material that is foreign, he’s simply telling you to look at the word, realize that is who you are and adjust your thoughts, words and lifestyle accordingly: [James 1:23-25]