Spirit children creep me out. Give me the scariest looking beast, and I won't budge. But a dead kid...and my blood runs cold. Bad past experience, that's all.
Personally, I wouldn't trust it. Most spirit children are not really children. They're much older and knowledgeable but they pretend to be children to gain your trust. Many forms of fae look like children and so do some of the most malevolent and devious entities I've ever dealt with. I've never met an authentic child spirit on this plane. Unless you knew this child in life and they are coming to you in the form you are familiar with, don't trust it. Our souls are far older than our bodies, and even if you don't believe in reincarnation, most religions believe that children spirits are immediately taken elsewhere and highly protected. So they have no place on our plane.
My friend sees a little spirit girl. So far, the girl is harmless, but things happen when she's around, caused by other spirits. It sounds as if your spirit is harmless. I wouldn't pay much attention to her, if I were you, otherwise it may end badly. Just experience speaking. I've seen my friend's spirit, too. She was harmless, but she did say don't trust everything. That was the first, last, and only time I saw her. SO, as I said, it may end badly. It may not. Just don't focus too much on her.
Well I have seen many children and none have been harmful but I do agree that some spirits nay try to look like children so you trust them. If I was you I would try to find out what it wants. If it has a message for you hear it out but if it says something like I want to be friends leave it alone.
"I've never met an authentic child spirit on this plane". There are many authentic child spirits who visit this plane . Have brought many a child in from the spirit realm to connect with their loved ones giving comfort and reassurance. It could be a memory link or someone you may know who past to the realm of spirit at a young age ? How does the spirit make you feel? Go with your gut feelings and try communicating with the child.