It's clear from your posts that you are thinking of others, not just yourself. It's not selfish to follow your own path.
Kids will pick up on your feelings about it. They are accepting generally, but if you present it like it's some horrible shameful thing, they will pick up on that, so you have to be comfortable with the idea when you talk to them. Also, their parents may tell them first and you might not have any say in it. Certainly before you talk to them, you should clear it with the parents.
If it is you who tells them, keeping it simple without hiding things is best. Like "I always felt like a boy inside, not a girl, so now I'm going to let myself be a boy. The first thing is I'm changing my name to .... "
Dennis