Masking - Advice?

Hi everyone,

I've got my Diagnosis Assessment coming up on Wednesday next week, I've been making a list of everything I can think of that affects me or I struggle with or just generally notice about myself. I see so many people talking about masking but it's something I can't seem to relate to.. and despite everything else on my list, I feel like this is like a big thing that I'm supposed to be experiencing and it might sound silly but could this mean I don't have ASD? 

During school (I'm 27 now) I was always seen as the weird kid so naturally I stayed pretty quiet, but while with friends I was just "me", as long as I had people nearby that I know, I didn't feel the need to be quiet or hide any part of me. But I wouldn't say that I try to hide myself or be someone I'm not while with others (no more than what I thought was normal), I'd just keep my head down and carry on quietly. But this has been my experience all through life, I'm just quieter around other people. I've never really felt like I can't be myself, my family have always allowed me to be myself and never shamed me for being quirky or weird etc. and neither have my friends they just accept me for me and don't really think of it as anything different, it's just me. 

Since growing up and being an adult there are certain things that I don't do while I'm not at home, but I've always seen it more as a "you're an adult now, you should know better" type of thing and again, I'm just quieter around other people, but isn't that just a normal thing anyway? 

I just feel like that's something I'm missing, it's so widely spoken about and recognised as a thing with ASD but masking really just doesn't seem to resonate with me. It almost feels like a deal-breaker, if that makes sense? Like it's something I should be experiencing? Or is it possible that because I have a good support network I've not felt the need to build up walls? I don't know, I just don't really understand it and I feel like I really, really should?