At the start, I'd have a character who has some basic defensive Earth ninjutsu and a few very light genjutsu techniques. Her needles would be a supplementary thing that would eventually become her main source, should the RP progress at all.

The idea would be using the needles to either enable or disable a person's strength using chakra points. Obviously that level of mastery is pretty intense, so as a child, there would be pretty much no chance she could succeed at that in any meaningful combat situation. Outside of combat, she might be able to make a guy forget about aches and pains, or she might be able to further inhibit an already beaten bad guy: but she'd basically be a defensive character at the start, who'd evolve into an extreme support as the RP progresses.