im sick of my gf constantly complaining

I, (16m) have been dating a girl I'll call Maria (14f) for about a year. Recently she's been complaining about me not spending time with her, and also getting unnecessarily mad about "problematic" jokes I make around her. Also, she had been upset with me because she said it was "unfair" that I didn't have plans for our anniversary, and I just wanted to go see a movie with my brother instead. But I feel like it isn't that big of an issue, because she knows I love her and I don't feel like it's necessary for me to prove anything to her. Anyways, last week she started texting me after school like "we need to talk, I can't do this, what's going on," blah blah blah. I opened her texts and it was basically an essay she wrote about how she feels unloved. I was having a really good day, and honestly I didn't feel like dealing with her shit. I told her I would go on a walk and respond to her later. A few hours pass (I did actually go on a walk) and I decide I'm still having a good day and don't want to ruin it by arguing with her, so I just let her know I needed a serious break from the relationship. So am I the asshole? I honestly just felt like she was stirring up unnecessary drama and it was really impacting my peace. I do feel kind of bad for doing what I did, but I felt like she expected too much from me, and I just don't have enough time for her needs. I have friends besides her, so idk why she gets so triggered when I hang with them but not her, like she's just being weird. And I didn't break up with her entirely, because I still think she's hot and I wanna do stuff with her, but I just don't have the emotional capacity to be her knight in shining armor constantly.

tl;dr: girlfriend mad I'm not "spending time" with her. I decide to take a break from the relationship because I think she's being irrational, but we're still "active"