What do you do about a step parent that acts like your actual parent?

Then have a discussion with your step mom . Tell her that you would prefer that you and her become friends , but that she shouldn’t act like she’s your mother because it makes you feel uncomfortable . But also remember that this is strange for her too ... just like it is for you . And she doesn’t know really how to interact with you . And trust me when I say she is just as stressed out about this situation as you are. She fell in love with your father ... not you . You have no history together... you don’t have a common interest since you don’t have mother/daughter love going . So forging your own unique relationship with her is the only way to make things not be so awkward . If you had that honest discussion with her ... she is going to feel so much better and just be herself around you .., which I suspect is very likable . And then you can do the same.