I would first say realize any fitness journey is about you. Do not compare yourself to others in the gym, in ads, on social media, or ever. It is about you and your progress in what you wish to accomplish. I didn’t start working out until I was 30 because I always thought people would be snickering at me saying “look at the fat kid trying to get in shape.” It was all in my head and many people are quite encouraging.
When starting out, focus on a schedule that works for you. Whether it is in the morning or evening, find the schedule that will work for you to get it done. You will need to adapt your life to implement it which will mean sacrifices in other areas. I like early morning workouts which means I tend to get to bed early which sacrifices time with loved ones and friends in the evenings. I may still do things but i then tend to use the next day as an off day if I’m out late.
If you join a gym, just showing up is half the battle. You will have good and bad days; days when you can run forever and days when you can barely walk (lookout for the days after legs). But show up and keep your schedule no matter what.
Listen to your body. Your body will tell you what you can do. Sure, push yourself but don’t sacrifice safety. That’s how injuries will occur (and they will occur).
there are tons of ways to train. Strength, stamina, bodybuilding, etc. you will eventually learn what you like and what your goals are which is why it is important to never compare yourself to others.
Read a lot of articles. Exercise routines, supplements, nutrition. Just read and use the advice that works best for you. Mens Health, Muscular Development etc are good generic resources. Lots of people have philosophies but look to the messages that are consistent between them all. Over time, you will develop routines in line with your goals.
Genetics matter. Not everyone is born to be a lean cardio machine not are we all born to be a hulking beast. Learn and understand what you are capable of achieving and accept that.
I started on cardio. I watched others (non creepy) and saw what they did during their workout. I learned from them. Then went to machines. Then To free weights as I was intimidated by them the most. Now, they’re my favorite.
so start by showing up. It’s the first step. Good luck!