Some fruits must remain on the vine to fully ripen. And all fruit can fully ripen while still attached to the vine. Interestingly, some fruit can be picked before it is fully ripe and continue to ripen. Berries, citrus fruit, grapes and watermelon are examples of fruit that are best left on the vine to ripen. Apples, bananas, avocados, peaches and pears are examples of fruit that can continue to ripen after being picked. When you came to faith you may have been in your childhood home, nurtured spiritually to the point of grasping the reality of God's redemptive love. Or your intersection with God that resulted in living faith may have occurred farther down the journey when you had detached from the vine (or the vine had separated from you). Nonetheless, the Lord knew the nature of your personal fruit and caused your faith to ripen to sweetness under His watchful tending. And when you have been grafted into His living plant the fruit of belief will continue to grow into the fruit of behavior.
John 15:5 "Yes, I am the vine; you are the branches. Those who remain in me, and I in them, will produce much fruit. For apart from me you can do nothing."