Me,Me,ME!

I am having a big problem it is about me and my grandma. My grandmother thinks that she can criticising me telling me that i should be more like my sister and grow up it is very hard when i try to tell her to to stop being so mean. my grandmother wnats to adopt us becuse my sister and i have been in fostercare sice we were little. it is hard to decide if i should go live with them or stay in fostercare and age out.i do not know what i should do.