Sad about missing my daughters last two years of high school.?

Just be there for her whenever she needs you. Listen to her when she needs to talk, without interjection opinion or criticism. And do not be sad for her. She has a great mom who cares which is already more than I had or many other kids have. You care and she cares and that is not a bad thing. Look at it from that perspective and the sadness will turn to joy.