Of course you are reasonable to ask her to either stop or to reduce it. If she is tagging you, she is disrespecting your right to a private life or to a more private life than her.
And of course she should respect your feelings.
You can unfriend her as well as you are obviously not using social media in the same way as her and that is ok.
I dont see how you could fell out with her about something so trivial. You ve got 2 different approach to it and thats ok.
I share more than my husband but a lot less than some of my friends, my husband asked me to stop tagging him and guess what i stopped and didnt get offended.
Talk to her.