Teach her what is appropriate and inappropriate behavior.
If she acts like this in school, people will notice.
She is 7.
So like 2nd grade? Or going to 3rd?
I work at my kids' school. This past year, there was a 2nd grader that took a liking to one of the adult Aides. A young guy. She'd go over to him, bat her eyelashes, and hang on him, playfully. It was like wresting an octopus. The Aide, had to, un-glue her from him. And he TOLD her it is not appropriate and all those proper Professional things as he is school staff, and people noticed. But it was the girl's behavior, that everyone noticed. Because, she was inappropriate and per her age. So of course the parent was told. And she finally, stopped. And she pouted about it. But she stopped.
You NEED to, talk to your daughter.
You are her Mom.
Not her "friend."
Take the lead. You cannot hesitate about things like this just because you want to be a Mom that your daughter will tell things to. You need to teach her, about boundaries and what is appropriate or inappropriate.
Maybe it is just a silly passing phase of her's etc. But still, you need to teach her and guide her on things.
Also for future reference: the 'American Girl' book series is good, and for Tweens. Look it up online, every bookstore has it. It has many topics.
Also she is 7 and is wanting a boyfriend.
What tv shows does she watch? Those geared toward Teens, or her age type shows? Maybe she is getting ideas about it, from the TV shows she watches. Those Teen shows, are often about boyfriend/girlfriend scenarios. And it is not for 7 year olds.