Sorry, hit post too soon!!
But yes. Your DD will be fine 
ADHD and the RSD side of it can make relationships hard. I remember at her age my relationships, especially my romantic relationships, were extremely intense and breakups especially were like the end of the world. Especially as I was always the one being broken up with. I can hand on heart say, that being broken up with was worse on me mentally, in terms of it messing with my head and making me irrational and "crazy" than my own boyfriend passing away from cancer when I was 21. Of course his death was the worst thing that ever happened to me, don't get me wrong, I was devastated. But he didn't make the choice to leave me, if you know what I mean? The relationship didn't end with someone rejecting me, he passed away, still loving and cherishing me till his last breath. THAT is how bad RSD can be, it can really be cataclysmic for someone with ADHD. But I AM learning more and more not to lash out, it can be so hard but I just wait for a while for the anger to pass, I might be pacing around the house to heavy metal, to physically process my anger but I refrain from taking it out on others for the most part. People with ADHD are also known for their temper, which can be volcanic 
May I ask which medication she is on? No worries if you'd rather keep that private of course, but I'm happy to share that I take Elvanse, 50mg and I'd say the effects are pretty subtle. Maybe it's not the right med for me but i find it works, just not to the desired strength. If you feel it isn't working as well as it should be, have her, or you, get in contact with her doctor and see if there is scope to increase her dose or perhaps try another medication.
All the best for you and your DD, OP. Living with ADHD is hard, especially as a woman and especially as a teen. She will learn coping methods as she goes through life though, and if these aren't her people she will find her people eventually. Keep supporting her like you have been, as best you can, I know my mum finds a lot of my ADHD traits difficult but I don't know what I'd do without her. Lots of love OP!!