I care about my girlfriend, but she doesn't show affection towards me
We're in high school and it's been about two months since we started dating. Don't get me wrong, I really like her. She's smart, cute, and is the kind of person who always does "the right thing," something that I absolutely love in a person; it's far too rare these days.
But often, I feel like I'm the only person putting anything into the relationship. I show her that I care about her. You know, I took her out to dinner on her birthday, compliment her outfit every now and then if I really like it, flirt with her, send her sweet texts occasionally if I miss her/can't spend time with her. I let her know that I'm always there for her. The usual stuff. But rarely does she do the same for me, and if she does, it's usually in response to something I do for her. I never get spontaneous texts (not even things like "I miss you" when I was on vacation), she doesn't initiate physical contact often (especially not in public), she doesn't really flirt. I accept that it may just be her personality- some people are more emotional than others- but at a certain point, it's like, come on.
Again, and I cannot stress this enough, I really don't feel like I'm being an emotionally abusive/clingy boyfriend. I have a life of my own that is completely separate from hers, friends, schoolwork, activities, etc. I don't call her demanding to know where she is or who she's with. I don't buy her gifts everyday, I don't shower her with melodramatic romantic poems or whatever, I don't get mad when our schedules conflict, etc.
I guess I'm just confused. I don't understand what I'm doing wrong, or what she wants me to do, or anything. I really like her and I want this relationship to last, but I'm worried that if things keep up like this, it may not.