Starting a discussion with my 10 year old daughter on having high functioning autism for the first time

Hi. I am new to the site, having recently moved back to the UK. My daughter is 10. Just before the move the school counsellor at my kids' last school said she thought it was likely that my daughter has autism (high functioning). This came after several years of challenges at school and at home (nothing extreme but enough unusual behaviour to ring some alarm bells. It was not immediately obvious to the counsellor especially as my daughter had several close friends and values friendship highly and has not educational problems as was as being a very good communicator. But she said this was typical with HF autism as children can learn to mimic social behaviour and find their own coping strategies to hide the issue). My daughter also has epilepsy and I understand the conditions are associated.

Having read up a bit on the subject I think the counsellor is correct as my daughter has many of what seem to be the 'typical behaviours' (difficulty with emotional regulation, inflexible outlook, resistance due to fear and anxiety of many new situations, socially awkward and difficulty forming friendships - though she sadly left behind two very good friends when we left our last home. I could list some more behaviours but these are the main ones). We don't have a diagnosis formally and I understand she would need formal assessment here to get that. I have asked for a referral but know this could be a long while.

However, as we are approaching transition to secondary it seems important we start dealing with this. My main concern right now is that my daughter is getting very anxious about this transition to having just now started to understand how large secondary schools are here. She has not really made new friends yet and really the whole stress and difficulty with a cross continental move is taking its toll on top of all this. I feel now would be a good time to try to explain to her that her feelings and challenges are linked to a specific neurological condition. (Right now she seems to be starting to label herself a depressive with 'black thoughts'). I know that having more understanding of the condition can help some children to cope better with being autistic. But I am afraid if I broach this topic alone without any advice from professionals I could do more harm than good. Can anyone give me some advice on how to approach this, what to say, what not to say etc.? Would anyone advise me not to talk about it before the assessment or before getting specific advice from a professional, especially if I am to actually use the term autism which seems a major step for us to take? I really feel its the right time for us to talk more about this, especially with the discussion about which secondary school that is looming and not an easy one to navigate. I don't just want to wait the 6 months or longer that the assessment might take. Any advice appreciated. Thx.