To try to mentor a boy without God's leading and help would most likely be doomed to failure or worse.

The same is true of the pastor, the missionary, the worship leader. It is true of every calling. Yet God doesn't hand any of them their ministry on a silver platter. God gives people the gifts and talents they need to succeed in the ministry he has prepared for them along with the wisdom and determination to make them happen. But then, he expects each person to put forth the effort to turn those talents and determination into success.

It is very much like the parable of the talents. The master did not hand the money to the servants and walk them over to the bank to invest it. He handed them the money and let them use their own abilities to do with the money as they saw fit. Upon his return, the master discovered that one of the servants, out of a sense of fear, had buried the money in the ground. That servant was called an evil and wicked servant and was cast out of the master's house. The evil he did was not an action he took, it was the lack of action, the wasting of the talents the master had entrusted him with. I pray that your fear does not lead you to become that servant.

But I need Him to lead me.

God is not a micro-manager. Throughout the bible, there are very few instances where God leads someone towards something specific. Once in a while he does tell someone to go preach in Nineveh or to visit a specific denizen of Sodom. But most of the time he gives very general instructions: "feed my lamb", "Go into all the world and preach the good news to all creation", "go and make disciples of all nations", etc. Yes, God does need to be the leader, but one should not be waiting for him to micromanage. It's far more typical for God to give you a vision, put a desire in your heart, and give you the skills and talents to make it happen than for him to hand deliver everything to you.

It's rare to hear the story of a pastor who was delivered a congregation without having put any work towards it himself. It's far more common for a pastor to put in the leg work, go to seminary, study, learn, intern, and then finally join a congregation or start a new one.

I've prayed about it, and this seems best for me

You choose the words "this seems the best for me" as opposed to "...and God let me know that..." or "...and the answer was..." or some other phrasing that would indicate the conclusion you reached was the result of getting an answer to that prayer. I find that somewhat interesting since it implies your prayer hasn't been answered. But what if it has? What if it was answered here today?