I didn't do great at all at school (not a "failure" either, so went under the radar). My year 8 (13 years) son is currently under assessment for HF ASD and ADHD - his lack of focus is worse than mine was but obviously I've read a lot about it and its dawned on me that I'm probably slightly on the spectrum, but in particular i have all the hallmarks of ADD. Too lazy too be hyperactive haha ... but all the comments from my parents and teachers (always daydreaming, looking out of the window, lazy, can't be bothered unless something fires her imagination ...) make sense.
I wasn't popular either, I had some friends but not many.
I did do ok in the end. I forced myself to become hyper organised and thrive on deadlines and pressure. If there's no adrenaline, I'm very distractable! I'm now a partner in a law firm. My parents seen a bit baffled by this after their struggles to get me engaged at school.
My son is affected more strongly and I think he'll need specialist support, but I feel sure he's got it in him to find his niche and succeed in his own way. I've been pushing to get a diagnosis since primary but i was firstly fobbed off, and the process is looooong once it does start.
What I'm trying to say is, your daughter may or may not have ADD but if she has, it's better to get the ball rolling early. It wasn't really a thing when i was young but if it was, a diagnosis and support might have saved me (and my parents and teachers) years of frustration, loss of confidence and exam retakes!