My parents were like this for a long time. I dont think they meant anything malicious by it, but they would become obviously frustrated and say similar things. It all stopped one day when I had enough and snapped. I told my mom that she didn't know what she was talking about and that her doing and saying those things were only stressing me out and making it worse. I think I said something along the lines of "you don't stutter, so don't act like you know what I need to be doing. Its not helpful at all." Ever since then they have been 1000x better and more patient. Idk how your mother is, but maybe its time to have a come-to-jesus talk with her. If she changes, awesome! And if not, then like you said, find someone else to practice with who understands and supports you. Im 31 and still stutter everyday. Keep pushing man, don't let negative people bring you down or make you feel less than.