I feel like my bestfriend is overcompensating for being short

For some context we're both 15 and we're both girls but i'm 5'6 and she's 4'11. She opened up to me once about how she feels everyone treats her as a kid because she's short and i comforted her about it. Recently i've been noticing how she's trying to be more dominant i guess? When we hangout with our other friends she walks in the front and leaves me in the back i pulled her aside and told her "can you match the rest of the group's pace? We also want to chat with you guys" and she told me that she's not going to adjust her pace for slow walkers and we should match hers. I can't remember more scenes but this is one off the top of my head. I dont know what to do and how to bring it up without me mentioning her height or anything.

I'll have to delete post soon since most of my friends use reddit