Well, truth be told, this seems like a rather interesting power. I would be inclined to allow it. The problem is, it doesn't have a downside. It's the ultimate support power for pretty much everything. And that doesn't fit. So I think a good way to balance this might be to work out the downside of this power.
Now the thing that immediately comes to mind with a power like this is "muse". Maybe she's a scion of a being like that. As a muse, she is probably a faerie of sorts, so in this case a changeling. If those are faerie powers, the character won't be able to just give the effects of her powers freely to other people. She needs to make a deal, and an equal one at that. Not because she wants to, but because those are the rules of the fay.
Another thing that I've seen come up with muses is that their powers come at a price that's more than the faerie deal thing. It's often described like a drug. People can do incredible things when under the influence of a muse, but once she's gone, they fall sick like they have withdrawal.
Though I think that might be a bit boring for a game, so let me suggest something else: The character can't really make someone lucky so their endeavors succeed, they can just siphon luck from the future. And their target has to pay the price sooner or later. A bit like sponsor debt from luck, if you will.
And we can maybe go a bit further. Maybe she also has learned to move around those "luck debts". So she might be able to push someone's luck and then push the debt onto someone else, making them unlucky in the process.
So from here, we could simply go for a simple "sponsored magic (luck)". It should encompass pretty much anything you might be able to do. You could ask for sponsor debt if you think the luck they spread out is too much and that it should require some balance. It's probably not so much a direct sponsor as much as a cosmic force. Call it Karma or what have you.
Maybe an idea for an additional mechanic, since sponsor debt might not fit too well, as described above. Maybe have a track like this:
You start out at 0. For every good luck you spread around, you go into the negative direction, giving you a bonus on doing bad luck magic, but a penalty on doing good luck magic. If you spread bad luck, you go into the positive direction. That way you can't just do either magic, you have to do both, or you get bad at the one you keep throwing out.
As an added power, you could go with allowing her to make a die roll succeed/fail without rolling, but the karma track moves to the end of the opposite side. And it should only be allowed if you are on the opposite side of the track already (though not necessarily the end).
I hope that isn't too confusing. I can try to rewrite this, if it is.