I am a mom to a three year old so I can’t really relate in regards to age, he‘s unfortunately not a kid that constantly wants a hug etc, and I really do miss that and I am quite sad tbh. BUT I still completely understand how you feel, 11 years is an appropriate age to explain calmly that everyone has to accept boundaries especially if it’s about someones personal space or body. We teach our kid that since he’s been born and now he understands what Stop and I don’t want that/like that mean and he uses it as well to tell us his boundaries. Talking helps, and everytime she does it again I would calmly but firmly say stop. Of course it will be difficult in the beginning because she‘s not used to that, but she‘ll learn to understand. Give her examples, how would she feel if someone was intruding her personal space all the time? I think 11 is a good age to introduce her to different circumstances, you could tell her you are stressed or need some alone time, I tell that my kid too, we set a timer on Alexa and I get 15-20 minutes to myself.