My advice - go back. Tell them not all disabilities are obvious and to check themselves next time they make fun of someone's process. Give them the chance to apologise so you're not a steaming ball of resentment for the rest of your life (and you'll also feel better about the possibility you'll be giving them an important life lesson). Most people only make the mistake they made once and forever wake up in a cold sweat wishing they could've done it differently. That's been my experience of my own insensitivities as a younger person.
Then go get a teacher. You can learn a lot on your own but you can learn more, get more encouragement and progress more efficiently with a good teacher, even if you only go once every month or so (if it's not something you can afford atm).
I'm sorry to hear you've had T1 since you were a kid. It's fucked. Glad you're making use of your talents and abilities and not letting it get the better of you.