Based off that compare/contrast list, I'd say it's better off not getting diagnosed. At least, in my opinion. It depends on how much you want your family to understand, and how much you doubt yourself.
Really all a diagnosis is, for someone who is a bit more on the high-functioning end, is just a doctor, who doesn't know you personally but rather professionally, confirming to you that you do have a funky brain. And honestly, I don't really see how that could be very reassuring. Maybe more like a second opinion, or third, or any other degree, if there are others (i.e. your family) who agree that you are different. The only thing is, with your family, they don't exactly know what it is that makes you different, unless you've told them and the case is that they don't believe you. Which is strange, assuming they are aware you are clearly different.
In my case, my family knows I am different, and always have been. However, I am increasingly learning how to act more and more "normal" each day, so it's not necessary for them to know that I have asperger's if all it will do is show them what exactly is wrong with me. I don't require the services that come with it nor the medications, so those cancel out, too. By this point, while acting "normal," I have passed as maybe a shy or just socially awkward tomboy. There are still things that have stuck with me, though, that still make me an aspie, that show that my brain is still wired differently. As long as I know that, and know that there are others out there like that, I feel at peace.
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