Important Context: I should note that while we are both American and did our BA/MA in the US, both of us have/will have gone abroad for our PhDs. My friend is applying to a university in the UK and has already made personal contact with potential supervisors in this department.
I completed my PhD a few years ago and have been working as a postdoc at a well-respected European university since. I have a friend from my master's degree, which we both completed about 8 years ago, with whom I have remained in contact and acted as a bit of an academic mentor for throughout our MA and now as she has decided to pursue a PhD. I have a solid understanding of her academic abilities (know most of her grades, for example, and worked with her in group projects and understand her learning abilities and academic drive) and her personal commit, which I do think would make her a good fit for a PhD.
My dilemma: She asked if I could act as an academic reference for her as she has not been in touch with any of our instructors from our MA in the past 8 years, and I do, of course, work in academia. In the moment, I said yes, but now that I have received the link and it specifically asks that I explain "how long I have known the candidate and in what capacity", I realize that I would need to note that I was a fellow student, not just explain when we met and what I believe her academic abilities to be.
I was originally assuming I could simply write something like, "I have known X since her time in Y degree at A school" and then proceed to explain different examples of her work ethic and abilities (of which I have many because, as I mentioned, I have been mentoring her and know her story in quite some detail). Now, I am wondering if it will be noticeable if that is all I say or if it will hurt her if I specifically mention that we were students together during that time and I have acted as an academic mentor to her since then.
QUESTION: Will it hurt her either way if I: (1) only mention knowing her from when she started her MA and specifically do not mention in what capacity or (2) do include that I was a fellow student with her in her MA?
P.S. I have read quite a few other questions here that are similar, but many of them seemed to be noting that the person could not actually speak to what the readers would want to know (i.e. academic performance and abilities), but I do believe I can speak confidently to such information.