I totally know how you feel about being daddy’s little girl. It’s a tough spot to get out of because, well, he is your dad and he thinks he's helping. Although the whole sitch won’t turn around in a blink of an eye, you can definitely get it moving with a couple simple steps.
First of all, show him that you’re not a little girl. What are some things you do that make you mature and able to handle some things on your own?
Let him know that you can deal with the teasing on your own or with some help... from people other than him. Now, this doesn’t mean you should just block him off from knowing about your life. Whenever the topic comes up, tell him that there is no need for him to "teach someone a lesson."
Let him know that you got your teacher to help you out or you confronted those guys on your own. He’ll get that he doesn’t have to step in every time.
Have a heart to heart
If those subtle moves don’t do the trick, it’s time to have a dad-to-daughter talking sesh. There a reason he’s being protective of you all the time and it’s because he cares. And since he cares about you, he’s probably gonna want to hear what you have to say… about anything!
So just sit him down and let him know what’s been bothering you. Of course, there’s no need to make him feel guilty. Make sure to show that you appreciate that he cares.
But clearly tell him that you’re uncomfortable when he takes it too far and that you are growing up… in a way that will make him proud.
He'll probably always be a protective father, and it will be hard for him to let go sometimes. But showing him that you can deal with things in a grown up way might help him think of you more like an 11 year old than a 5 year old.