I don't really understand the differences between Light and Dark, or alignment for any Force user for that matter. I mean, would it be considered "Grey" if she was able to use things like Force choke? I envision a healer who is more of a battle medic than a dedicated healer. So, not sure on that.
I cannot say for certain I see her being like evil Dark but I can see her not allowing Light-sided principles to dictate if she lives or dies.
Well, there is a bit of personal interpretation to the Force between everyone who writes it. Some folks don't even believe 'Grey' Force Users should exist so.... I will give you my own interpretation to do with what you want.
Being a 'Light Side' Force User effectively translate to a sort of..... monastic asceticism. You're meant to largely detach yourself from personal wants,"earthly" pleasure, and focus on the will of the Force. Think of the various vows and tenants of Catholicism or Transcendentalism from Buddhism. Though there is obviously a bit of wiggle room you're more or less going to see Light-Siders be much more akin to idealized heroes and legends, always seeking to do what is right, while having a handle on their emotions ranging from 'under control' to 'smothered' depending on how the character/person reacts personally to such a level of supposed detachment.
Being a 'Dark Side' Force User translates to being much more, if not entirely, open to your wants and desires coloring how you reach out to the Force. Drawing power and advancement from your rage, anger, fear, even obsessions such as wanting to master swordsmanship or crafting. It's more or less a direct inverse of the Light Side wherein your main concerns fall on how the Force can serve your physical, direct means. Rather than you leaning into spiritualism to serve the Force.
Being a 'Grey' Force User, as the name implies, means something between these two and is (at least in my opinion) the easiest type of Force User to get completely wrong. Some people simply see being a Grey Force User as a way to get access to the 'cool' abilities the Sith (The name for the big Dark Side group) get access to while also not having to act like a psychopath. IE: All the reward, none of the risk. If you were going to aim for being a Grey it can honestly mean anything so as for what is specifically "IS" definitively I can't tell you. I would only give advice in that if you want to write someone who is Grey it should detail a lot of how both extremes, Light and Dark, have a natural calling to them. The Force tends toward these extremes, or perhaps it's better to say living beings do, as while it is ALWAYS a temptation to use this innate power you have for your own selfish ends (Dark Side) I also think it's kind of alluring to focus on the spiritual transcendence offered by detaching yourself from the physical as much as you can. (The Light Side)
Anyways, sorry, didn't mean to write a small thesis on the Force Alignments but I hope you find this helpful. ^_^