This question came up in a reading group over at GoodReads, and I noticed that I'm the only one answering in the affirmative, so I needed to make a post.
Yes, I do trust that books I considered good when I was a child were good.
That said, I realize this might seem a bit obnoxious: I mean, I was a child, right? Well, right, but I think I was a slightly particular child. Meaning, I did not read what other folks my age would - that's one of the reasons I have so much trouble with graded readings, by the way: I can never tell if the age group the book's intended for is well defined, because I can't compare it with my, say, ten-year-old self. Want an example? Okay, let's see:
Summer break for my eleven-year-old self involved The Aeneid, The Oddissey and The Illiad, in that order. Not parent-enforced reading, but following my own choice. Actually, I recall my family to be quite appalled when I asked them to buy me the last two books... And those are the ones I considered great reads, even back then, along with Much Ado About Nothing and Pride and Prejudice.
I also enjoyed children reads: there's a book called Kasperle (sorry, can't find a translation in English right now) that I don't remember reading for the first time (my Mom had to read it with me, but no, it was not a picture book) and I regularly re-read it yearly until I was fourteen or so. Since then, frequency has decreased due to the huge amount of new books and just to my personal workload, but I still can pluck it from the library and enjoy it. I found it captivating when a child, and even now can appreciate the pacing, humor and the educative value. If I had to guess today, I'd say it was an eigth to ten year-old read.
Momo is a somewhat darker tale - at least if you read it at seven or eight! It's not very well known, not when compared to the Neverending Story (same author), but it taught me a lot of things about life (and kept me sitting on edge!) and I find that re-reading it will remind me of the importance of those lessons.
Finally, in that same age-group, there's the Little Vampire - I just loved that series, I think it's the only reason I have a healthy obsession with vampires today! And before you ask, yes: I still have the whole collection in my house - and I still read them randomly and laugh at the situation.
That is the full amount of books I considered amazing when a child, and I still stick by my old judgement. What about you?