Well, hello there fellow UK person!
Yeah, I’m not surprised that you’ve received a bad reaction, based on my own experiences, and based on research I’ve done since. I’ve, so far, told my Dad, Brother, Mother, Fiancee, Boss, and Father-in-Law (to be), and two or three friends. For various reasons, my Mother-in-Law (to be) knows, too. The only wholly supportive responses I’ve had have been from the friends (who I’ve known for donkey’s years) and my Fiancee and Brother.
The largest issue I find is that so many people only have a vague idea of what ADHD looks like, and no clue about the underlying causes. You could have a little fun with some people and explain that you think you have ‘executive function disorder’, and explain it the same way you explain your adhd symptoms. I can pretty much guarantee you’d get a better response because it’s an ‘off-brand’ condition, if you like 😛
But enough joking for now. I wouldn’t ever call it a bad idea to tell people, generally. But, perhaps try to be more discerning with who you tell. And make sure you have the facts about ADHD clear in your head. That it’s caused by insufficient dopamine production in the brain, which causes issues with executive function (the thing that allows you to prioritise tasks, information, and concentration). While you can mitigate it with techniques, practices, and habits, that doesn’t work for everybody, and you MAY need meds. No, they won’t rob you of your creativity or intelligence, and if they SEEM to, then you’re on the wrong medication, and need to try a different one. As for your friend who says she shares the same thing, explain that there’s a difference between forgetting to call someone every now and again, and forgetting something you’re told in the time it takes to pull out a chair, or open the fridge. Everyone loses their keys, but do they ever lose theirs three times a week? If they do, then they should probably look into getting tested, too.
At the end of the day, despite what a lot of people seem to think, getting diagnosed is not the ‘end point’, after which your life is effectively over. Instead, it’s the beginning of your BEST POSSIBLE life, where the issues you face that make things harder for you than for others hopefully start to get solved, and you can get along with being the you you actually want to be, rather than the you you have to put up with as a fact of being alive.
If you have a teacher or close friend who you would trust to support you, I’d recommend confiding in them while you go through this process, and then later on taking your diagnosis to the naysayers and telling them where to stick their condescension. Read up on how ADHD ACTUALLY works, and what meds ACTUALLY do, so that you can correct anyone who tells you utter rubbish, and if they don’t like it, tell them to go do their own research, or shut the hell up and leave you alone. At the end of the day, as you know, ADHD is very much real, medication CAN be very effective in helping the symptoms, and your struggles are not as simple as ‘occasionally being a little ditzy, and just need to write more things down’. Writing down obligations and appointments doesn’t do shit if you forget the piece of paper you wrote them on even exists.
Sorry, I’ve ranted, and I’ve maybe been a little more crass than I normally would. I’m sharing quite a few of your frustrations currently, particularly with my boss. I hope things go well for you, fellow British person.
TL:DR- You can tell whoever you like, their responses depend on how much they know and understand. Educate yourself so you can protect yourself against the naysayers.