I would just like to echo what others have already said: first, it’s important to apologize (not only is it important as a fresh start for both of you, but it’s a great example to show her that you are only human and that it’s normal to make mistakes) and second, focus on developing a strong relationship with her. Find things about her that you really like and admire, and let her know that you do (one great way to do this is to find out an interest or hobby she has and then share with her-have her teach you or do a project together.) Spend time together having fun, being silly, laughing together. Talk about inconsequential things and ask open ended questions to find out what she thinks and how she feels (and resist the urge to give advice, unless she asks!) Figure out her “love language” and make sure you ‘communicate’ to her in that way (is it quality time or words of affirmation or gifts or touch? If you don’t know, try all 4 of them; you can never be too loving!) You could also consider doing some mother/daughter counseling together as a jumping off point for learning some new ways of dealing with things (for both of you) and learning some new communication and coping skills.
It’s never too late to make things better (and your efforts to do so will show her more than words ever can that she is WORTH the effort to you). A strong, loving, mutually-respectful relationship will give you the foundation you need to be able to handle together whatever struggles she has in the future, academic or otherwise.
Hope this helps!
Parenting Coach, school counselor, author, mom of adult son with ADHD