I've been told that for YA literature, most editors want it told in 1st person POV. The rationale is that 1st person is more intimate, and young readers can identify better with the main, or POV character.Two words: Harry Potter.
I’m not sure I totally agree with that. I've been writing a YA novel in 3rd person, and I think it is very intimate, getting into the thoughts, feelings, emotions, etc. of 4 different characters, all having their own stories (sub-plots) that tie into the main character’s story. I was told recently that I should re-write it in 1st person as most editors won’t accept one written in 3rd person. If I were to re-write it, I think it would lose a lot, as I would have to cut out all the sub-plots that give the main story so much richness.
Is there any truth to that rumor?
Added to original post:
Perhaps I need to give more than a two word answer. Harry Potter, the biggest selling children's/YA series in the history of the world, is written in third person.
First person works very well for YA books for the reasons you list but it's not the only way to write. Do what works best for your story.