Where had Harry's confidence gone?
When Arthur first met Harry during his former life, the man was a fairly confident, wise man in his thirties. He was a fair leader, and one of the greatest men Arthur met at the time. Although, his strength was not significant.
However, despite his lack of strength, Harry led Stars Of Tomorrow into prosperity, solidifying their name in the mid-rank clan range.
Such a man would have never feared biting off more than he could chew. He was confident, and even impulsive sometimes. His ability originated from the massive force he amassed during the tutorial.
However, wouldn't his start be terrible if he couldn't amass a similar force this time?