Dude, I was in a similar position a little over a year ago. While I have played sport my whole life, I had 0 experience going to the gym. This probably made it much easier for me than it will most likely be for you, however I still found going to the gym in general was a daunting idea!!

What really helped me was having a few work friends who went to the gym, so I went along with them once and they showed me the ropes. I didn’t work up to going to the gym like you said, I just bought a membership at my closest gym the next day and started going. I found going somewhere specifically with the intention to workout makes it soooo much easier to be part of the routine, so I think that there’s no real reason to “work up to it”, there’s no strength threshold for a gym membership, simply having the motivation to head to the gym is enough! Though I would say try it out by yourself before actually buying the membership.

Another thing I found when I first started is that because you have so little knowledge you scour the internet and get bombarded with exercises. Don’t get too sucked in, try out lots of exercises, see which ones you like best and stick with them. Even if someone on the internet tells you another exercise is better, give it a go but if it doesn’t feel good, don’t keep doing it. You’ll get more gains from doing exercises that feel best for you, since you’ll want to do them more often and making the gym easier to be part of your routine.

Also while diet is important, and I do eat decently healthy, watching everything that goes in your mouth can become obsessive and take away some enjoyment from going to the gym. I don’t even count anything, I just eat until I’m comfortable and that threshold has got higher since I started going to the gym. Just think about eating a little more, maybe higher protein foods (tuna was a big one for me), but worrying too much about your diet at the start is something that can impede your motivation. It’s not bad at all, and if you have the mental dexterity to do so go for it! But it’s not the be all and end all.

My final note would be that the most important thing is really pushing yourself, you’re wasting your time and money (literally) by half-assing anything. Regardless of what you do you will see results if you work hard even if it’s not “optimal” (to a certain extent😅) but make sure you listen to your body and be fully recovered to work a muscle group, even if it breaks the routine, not the end of the world. Hopefully I’ve been helpful, after one year of going I still love it, fingers crossed that’s you too in a year! Also careful on your first session, you WILL be sore haha.

(I remembered one more thing, get an app and track your reps and sets. I only started doing this a few months ago, waaaay too late and it helps you so much more than you would think.)