Can My Mom Do Whatever She Wants with Me

My question involves juvenile law in the State of: california

i am a 17yr old girl, soon to be 18 in a couple of months, and i need to know if my mom can do what she pleases with me.

About a several months back i got into this big problem with her she thinks that im the worst person out there. she accuses me of consuming drugs, being in wrong crowds and other horrible lies! she sent me to mexico with my grandmother and she took my passport and any sort of id i possesed. i want to go back but i dont know how because she said she wouldnt let me go back until she felt like it. i have not finished high school yet and i am angry that she is going to make me lose a whole year.

awhile back she came for me but she put a lot of conditions and she said that if i didnt follow them she was going to send me to a correctional center in TJ. i really felt that i was going to fail so i decided to stay in mexico.

i am now trying to reason with her. ive been calling and talking to her nicely and letting her see that i deserve to be back there in LA. she has been thinking about it and i really feel that i am getting to her BUT the thing that really has me worried is that she told me that i might go back but if i mess up one more time shes going to make me pay and that im going to be sorry that i lied to her. i know she wouldnt hurt me physically or anything like that. im worried that she might do something legally . so i want to know how much power does she have over me after i turn 18?! im planing to move out as soon as possible if things dont go well with her. its just that im afraid that she might somehow keep me with her even if i dont want to. i really need help!