I KNOW how to do this!

I'm not even sure where to start this... I guess some background info first.

I lived on my own for 3 years (before the economy took a dive), I had to walk everywhere I went, I cooked my own food, and took care of myself like anyone else would/could.
When my father lost his job (a something like $14/hr job), he and my mother started to struggle with finances, so when my apartment contract was up I decided to rent a room from them in their house, this way I could help them financially and I'd have an internet connection as well (can't afford one normally). Which is where I have been ever since, even now as I type this, I'm in the room I have been renting this whole time.

The catch is, my mother is obsessive about everything. She's learned over time that it gets in everyone's way and for some things she leaves well enough alone, but for whatever reason, she takes the assumption that I don't know how to cook, despite the fact that it has always come naturally to me and I have proven that I can multiple times (afterall, I didn't live off of food that doesn't need cooking for 3 years straight).

So, today I asked if I could bake some cookies (the ONLY reason I asked instead of just doing it is because I didn't know if we had everything that was needed to make them) and she treated the question with "do you know how to make my cookies?". The answer is "yes, I've baked cookies before when I did so at the local deli, from start to finish, for the better part of a year" (not to mention the fact that I've watched the process for like 20 years as well). She pulls out a recipe card (that apparently has incorrect instructions for whatever reason) and says "well, you can't go by this because that's wrong", I said "that's fine, I know how to do it, I did it for like a year making slightly larger ones at [the deli]". Her reply was "that's not the same thing" and then dismissed the possibility, telling me that I couldn't go ahead and make them because she didn't have time to "explain how".

The only difference is time and maybe a slight reduction in temperature to prevent burning.

The frustrating thing is, this happens for everything she hasn't witnessed me cooking. It's honestly insulting and humiliating. I know what I'm doing even if she doesn't think so.

A while back we all decided to take days that each of us would cook because of a lack of time on my mother and father's parts, that lasted a week because she couldn't keep out of the kitchen and let me work, constantly looking over my shoulder and pointing out flaws that didn't exist while insisting that I don't know how to do something. I quit after that because it was insulting just as much then as it is now.

I'm the oldest sibling between us three.
My brother (who has no experience cooking and likely won't with the way our mother is constantly acting) also has AS (though nowhere near as severe as me because he had help early on enough to adapt to normal life), and has to deal with the same, though I've only seen a few times where that's the case.
My sister on the other hand, has always been fairly trusted with stuff. She doesn't have AS and leads a perfectly normal life. The catch is, she has botched 10 times more things that she was cooking in one year than I have in my whole life. Yet she has our mother's full confidence in all things cooking, on the whole.

A number of years ago (probably 6), my mother also made predictions on who would likely do best vs. worst. She always had confidence in my sister for just about everything, but when it came to me her predictions and fears were as follows:

Fear of me living on my own due to leaving the stove on and it catching fire. (Seriously?)
Ratio of me forgetting to turn off the stove: 0%
How often I triple check that I've shut it off: 100%
The only person in the family to set fire to the stove: Sister
Person who put it out: Me
Problem they [parents] found with it (yes, they found a problem with me putting out a fire): Using a fire extinguisher instead of something else that could've put it out, and not coming to get them first.

(I was in disbelief, obviously, that they found fault in putting out a fire)

Fear in me cooking something, in fear that I'll screw it up somehow.
As stated previously, my sister has screwed up more, cooking stuff, than I ever have. Yet she's given more confidence in cooking than me.

I took cooking class in high school, aced it and then some.

I KNOW how to cook! It's not rocket science and frankly, I can cook better than them.

One of the bad things is, my brother, who is 17, has never been given the opportunity to properly learn how to cook multiple meals. He knows how to do simple things, but that's all, and that's the only things that our mother trusts either one of us with.

Honestly, it's off-putting and insulting to be told not to cook something because someone doesn't believe in my capabilities as a cook.

It boils down to two possibilites:

A) She doesn't believe in my capabilities and likely never will.

or

B) She doesn't trust me.

Honestly, I think it's B. Over the years it's been painfully obvious that no-one here (aside from maybe my brother) believes 90% of what I say, regardless of what it is.

[Rant=begin] It's been that way since I was a little kid, even when it was so obvious I didn't do something, I'd say "I didn't do it, [sister] was the only one downstairs!", all she had to do was lie about it and she was believed.

The only reason I'm still here is because of the internet connection at this point. I can't afford one on my own (I can barely afford a basic cell phone, living on my own) and without one, I'd not only be bored out of my skull, but also unable to work on my projects (some of which I will likely be making money from) and talk to the few friends I have left. The noise here is unbearable on most days, with a dog that constantly (no, seriously, every 2 minutes he starts and won't shut up for like a half hour) barks, others laughing louder than necessary, interuptions when they have to walk through my room to let the dogs outside, the works. [Rant=end]

Ugh! I'm just tired of being treated like I don't know what I'm doing and don't know anything!