It's normal to be sad at times as they grow up but you're taking it far too personally and as life changes, you need to shift how you're going about connecting with her and allow her to choose how she connects with you.
My teenagers and I have butted head sometimes as we all change, our schedules keep changing and we're all getting busier, and we have to refigure things out. Sometimes, that does mean I do less -- as a pp said, stop giving everything. We've long had a policy where I will help with school stuff as much as they put in because otherwise I get resentful & that's not fair on anyone - them or me. As they do more things on their own, I'm working to find more of my own things too.
Really, what's worked for me is not looking at all day possibilities, but things in an afternoon or an evening that I already enjoy, but they can dip in and out of - so once a week or so, we do multiplayer games for the one afternoon no one has an activity, the younger kids always take part, and sometimes the teens join in too. Same for walks, for trips to town I'll often say I'm going to be in town for X reason, do you want to meet up for Y? and send them a text at the time. Sometimes they do, sometimes they don't. It's more giving the option to take part in your wider life and taking that option if and when they give it to you.
Do some parents forget their own teenage years when they get older?
I think it's more they're trying to pre-empt some of the riskier things they did and/or they didn't have a very good example to go from their parents.
I'm mostly in the latter category and fully admit to winging everything - my poor guinea pig eldest and I have had discussions on that. My parents were too busy still acting like stereotypical teenagers to parent to the point I now look at my teenagers and their baby faces & struggles and get really pissed off how I was left to flounder because my parents wanted to party, but I have to temper that desire to not let my kids go through with allowing them to become independent and start choosing how they want to connect with me. It can be hard sometimes, but at least I'm not making shame diaries. I'm not even doing the classic curse of 'may you have a child just like you' which was very popular among adults when I was growing up.