Im in highschool. this girl who is in some of my classes likes to tease me and do impressions of me playfully. aside from teasing her back what else can i do

she likes you. Everything now sounds like attraction. Keep this going, but at the same time, start building comfort and set up a day 2 with her.

well, we can't assume that she likes him, she could be a friend teasing a friend. how far are you with this girl? has she given any IOI?

We tease each other a lot in a fun playful manner, sometimes if I'm walking she will come out of nowhere and push me or Sometimes she will push me and run away waiting for me to get her back. We play fight tease each other a lot. but sometimes she goes cold, like one minute we are talking laughing next minute she gets all serious and doesnt look like shes in the mood, then she goes back to normal. I dont know how to react when she does it, is she serious? is it a test ? Maybe she doesn't want to seem easy (slut). How do you guys react when a girl does this? And am I in a good situation?