I hope that there's a difference between being childish and childlike and that I'm the latter, if you take my meaning. I often sort of wonder. I don't think I'm a terribly good grown-up; I don't take responsibility easily or well in many areas of life. Finance and stuff like that, I'm absolutely appalling.

This quote is saying that the speaker wonders if there is a difference between being childish and childlike. They believe they are the latter, meaning they have characteristics that are typical of a child but in a positive way. The speaker is struggling as an adult and does not take responsibility for their actions and does not do well at dealing with money.