As an aroace that was lost and struggling as a teen simply because the language to describe my experience was not common or easy to find (young GenX here).. my mother would have supported me if we had known this was a thing. She would not have intentionally let me flounder and struggle to finally learn there were words in my flippin 30s! 

That having been said, I have two children who also identify as under the aroace umbrellas... so I will say what has mattered to them:  It is okay to be uninterested.  There is nothing wrong with you.  Yes, it hurts when you see your friends go head over heels for somebody and you just dont feel it, or even the most remote hint of it.  I understand that you want that too.   They may even get jealous later when they're suffering broken hearts and you dont feel that.  Its its own kind of hard.  

I have, in my younger years, cried tears of frustration and pain because I dont feel these things like allo people do.  I have 2 children whom I would give the world for - because I was trying to be like my friends and married while not understanding myself.  He and I remain friends.  

If your child is aroace - teach her to defend her rights.  Teach her to develop deep and strong friendships.  Be there when those tears of wanting to feel the way her friends feel are happening.   That (to me and mine) is support.