If transitioning truly will make things worse than perhaps you are right. You shouldn't. But wait a minute what about a year from now? Two years? Five? You don't have to live with or be around people who treat you like an idiot forever. If someone loves you, and I mean really cares about you they will respect you, your needs and your decisions. Stop trying to please your mother. She sounds selfish. Don't live your life trying to be what she wants you to be. You will never be happy. And if you dont resent her now, you will. You aren't dumb and if you truly don't have any talent than you can learn. You can develop talent.
Your mother will only be right about you if you let her. Take her doubts and hurtful words and use that. Use it to prove her wrong. Let it be what motivates you if you must. Often times artist use their emotions and stuggles to better themselves. You can throw all your emotions onto a canvas in the form a painting. Scribble out your struggles onto a piece of paper in the form of a book or a poem. Take those hurtful, hateful, selfish words and crush them as you continue to learn and better yourself for you.
It sounds like your surrounded by people who don't believe in you or believe you. So much so that you even feel the same way. I know how that is, to an extent. I've been in a similar situation but for different reasons. I was depressed. I was numb and thought my very existence was pointless. But I can't really say I know you feel. Because I don't. But I know how it is to have people that are suppose to help you up when you are down, be the ones you are putting you down. When you look around for a hand to help you up but there aren't any. Instead of getting up for the millionth time you just don't even want to bother.
When words fail take action. And by that I mean, since no one will hear your words, learn the languages you want to. Learn programming. Get better at math and art. Love who you love. If these things make YOU happy than do them. If your mother is disappointed than let her be disappointed. You need something that makes you happy. Whether its that half hour you spent learning how to say 'bread', 'pants', and 'banana' in another language or those ten minutes you spent learning how to draw a dogs ear. Those little things can be everything you need to get through the day. If it means your mother is disappointed than so be it. Its your life.
Now I don't know your whole situation so if trying to live your life in ways that makes you happy is currently dangerous than by all means, wait. If its better and safer for you to wait, than wait. But keep in mind that there is hope. You are so much more than what others think of you. Every person has potential. Please do not let the people around you ruin yours. It's there.
I'm sorry if this is all over the place. Haven't quite finished my coffee so my brain is still waking up. But I wish you the best and hope you can start feeling better about yourself.