The Lord left certain nations in the land to test those Israelites who had not participated in the wars of Canaan. He did this to teach warfare to generations of Israelites who had no experience in battle.
We all have to face battles and trials. No one else can pass through our trials for us. The hour will surely come when we must face the enemy for ourselves. Parents, pastors, and counselors may shield us from warfare for a season, but the day will come when God allows us to walk into the battle alone. He does this so that we can testify of His faithfulness—a faithfulness that we have personally observed. Another reason He allows us to face the enemy is to see whether we will obey His commands (Judges 3:4).
Peter discovered that he had more “mouth” than “might” (Luke 22:33). As long as Jesus was around, he could really talk a good battle. However, the moment Jesus was gone, Peter denied that he even knew the Lord!
Your first “solo battle” may be a little shaky, and you may even fail. But take your licks, learn from the battle, and rejoice that the battle belongs to the Lord (1 Samuel 17:47).