This was me a few years back. I'd always done informal IT fixing for family and friends, and I went to school for a network support cert that never really manifested into a job until I went to a job support charity that helped me get this job. They basically threw me in the deep end- ostensibly I work on helpdesk, but we're a small org so I have to fix things considerably deeper than a malfunctioning word doc- firewalls, vpn tunnels, servers, etc. As is tradition, I knocked a production environment down on my third week on the job post training, learned from it, moved on, and these days have become a core team member and am often relied upon by my boss and coworkers to solve things that stump everyone else.

My greatest strength is probably being able to pattern match my way to solving stuff- picking up bits and pieces, researching online, and putting solutions together that other people just don't have the mindset for. All the time I get asked- 'Skyraker how did you figure out X, I googled it and couldn't find anything' and I'm looking at my notes and really I just googled it, discarded all the results that were off topic, opened three tabs, tried the solutions there, filtered my search results based on what didn't work, found some old post on a 10 year old forum that said a similar issue was fixed by installing this software from the vendor that isn't offered anymore, go on archive.org and check if they have it- if they do, great, if they don't, reach further in my bag of tricks to find the program (sometimes contacting vendors), get a copy of the software, run it in our test environment, it fixes everything great! document the fix and deploy, get things up and working.

You just gotta have persistence and drive to keep at an issue until you find a fix. Most anything, the fix is out there online. And when it isn't, don't be afraid to ask your seniors for help when you can't figure it out. Don't be afraid to phone vendors, even when they'll have never heard of you and the only place you found their phone number was on a PDF manual from 20 years ago and you aren't sure if it even goes to the same place.

spoilers: I used the phone number to locate their current website, they had totally rebranded and were under a different name and were chuffed to provide support for their old software.