I have made some changes in it. Hope this is eligible to stay open on this community.
If you really want this reopened, I'd suggest following Kilisi's advice. You could summarise your entire question into a variation of your last sentence:
How should a newcomer to the workplace act to build a reputation as a dependable coworker and lose the "newbie" tag?
The wall of text you give describing your situation confuses your post and detracts from your argument because you're seeing belittlement and condescension when they probably aren't there. You are the new kid on the block. People are used to newcomers feeling overconfident or pretending to know the ins-and-outs of expensive equipment when they haven't even mastered the basics. 'Harmless' comments or jokes about age, appearance and body image are incredibly problematic and while society is becoming more aware of that they are still common.
Unfortunately, I think the only answer is "take the chip off your shoulder, focus on simply demonstrating that you're a competent member of the team, accept that until someone else joins you're going to be 'the kid' and that there is nothing malicious about that nor anything to be embarrassed about, and recognise that everyone does a few minor tasks like helping with a trivial piece of equipment simply because friends do that for each other."
I'm not sure whether that makes this a usefully answerable question or not. I think so, but I don't think it's an answer the OP will appreciate.