"Whoever trusts in his own mind is a fool,but he who walks in wisdom will be delivered." --Proverbs 28:26 (ESV)
Over the years I have been blessed by a number of great preachers and teachers. Not all of them were formally educated, so they were referred to as "self-taught". Most of these were much more than "self-taught" since they steeped themselves in the wisdom of the ages. He who walks with the wise is wise.
Solomon warned that those who are satisfied with their own insight are foolish indeed. The limits of self focused knowledge are many and the depth of such a one is quite shallow. Whether one has formal degrees or not, they need to remain a student to make a difference in life. He who walks with the wise is wise.
What efforts are you making to add to your learning my friend? Who have you chosen to serve on your "faculty" of teachers? Have you remained a student of the Scriptures, no matter how many years have passed? Don't rest in what you already know, because there is so much more to learn. He who walks with the wise is wise.