What everyone else says, OP. I’m pretty fit - gym goer 3or 4 times a week, plus all sorts of dance classes. I still get out of breath and bright pink if I’m working hard! In my personal trainer sessions, my trainer says if I have enough breath to swear at him, I’m not working hard enough.
Starting out is great - congratulations! A yoga teacher once said to me that the main effort was getting to the mat. Once you’re there, you’ve really done the main thing. Keep a record of what you do and you’ll see the progress you’re making. That can be very motivating.
My BIG advice is - start very very easily. Don’t do too much all at once. Just walk on the treadmill at your usual pace, for example. And maybe each session, add a bit of an inclune. Working up to walking at, say 6km an hour, but at a relatively steep incline (like 7 or 8%) will give you as good a heart and body work out as running in the early stages of getting fit.
I find it helps by Having a regular routine of when I go to the gym and what I do there, so it becomes automatic.
Also, get the gym staff to show you how to stretch after a work out (don’t stretch beforehand). That will help with muscle recovery and the dreaded DOMS.
The other tip I’d give is to go to your gyms fitness classes at least once a week. It’s motivating as a good instructor will teach you stuff about how your body works, and it’s more enjoyable to suffer in company! Maybe do gentle stuff like Pilates, rather aerobics though. It also makes financial sense as you sort pay for your gym membership that way.
Take it slooooowly. Better to take longer and stick with it than go he’ll for leather, get sore or injured and give up. —looking sternly at my younger self—