> To be more specific: They're going to laugh at me because I have no idea WTF I'm doing.
This was my exact fear as well. I included BMI in my reply to illustrate I had never stepped foot in a gym before but perhaps that was a mistake to focus on.
In fact I could have written your entire post nearly verbatim 2 years ago. Even down to the "what do I wear" question. I was terrified for all the reasons you list, and am in general quite socially anxious from the get-go. Especially in totally alien environments to me. I spent months selecting gym wear and a bag prior to first stepping foot in one.
> and that those who do go to gyms all seem to have the broad assumption that everyone was born with the specific knowledge needed to go to the gym, and that it is all implicitly obvious to anyone who is breathing.
This is an assumption I held as well, but is simply outright wrong. The folks who are hardcore gymgoers love nothing more than helping newbies out, and they don't make these assumptions in my experience. They have a hard time not coming over and helping you out with proper form if they see you doing something that might injure you. They don't do so because they are afraid of making you uncomfortable. If anything, they get excited to see someone putting in the consistent work - they know how hard it is to do so, and love to see people attempting to improve their lives since they generally know how positive it is in theirs. There are assholes in all demographics, but they are rare in my experience.
My first trip to the gym with a personal trainer was highly specific: I want to be taught like a 5 year old on the easy machines so I can use them without feeling like an idiot on my own. This lasted a few sessions and definitely was a totally new experience for my trainer. She obviously felt a bit uncomfortable doing it since it was so far off-script for her.
Over time I graduated to feeling a lot more comfortable, but those first few months were really difficult for the reasons you describe. I felt like an outsider and a complete idiot since I barely had a clue. At some point I just surrendered to looking like a moron.
I am very lucky I have a wife who is very socially capable and was in the gym a lot beforehand. I was able to use her to setup that first training appointment and explain how out of the ordinary I wanted it to go. Otherwise though, I did it on my own with said professional help once a week.
I honestly wish you were close to me (maybe you are?) because I'd love to bring you to my gym and take you around - tell my trainer there is another one of me who needs the same treatment! It was life changing to me and I wish I had figured out a way to do it sooner in my life.
I still feel awkward as hell in the gym. I do half my routine "wrong" and still feel self conscious about it. But I'm slowly getting better, and I slowly realize literally no one cares.
If I can work up the courage, anyone I ask is quite happy to show me proper form/give advice vs. judgement. I'm sure a few do judge, but they thankfully keep it to themselves. I also continued to work with a trainer and developed a nice rapport where she can laugh at me in a good way while we correct my fuckups with a sense of humor about it all. She's basically become a family friend at this point.
Even with all that said, I now look forward to my training sessions. Less so my solo trips, but I feel amazing afterwards. Both physically, and the sense of accomplishment. So many of my "feeling like shit" days have been cleared up, and I now have a little bit of self confidence in my strength as well.