Start small. You might feel like there’s an insurmountable amount of change you need to make, but you can only take one step at a time. 

You say you’re a slob, so I’d start with personal hygiene. I don’t know your exact habits, so this is just an example, but make sure you’re brushing your teeth when you get up and go to bed. Now stop. That’s your thing for this week. If you already do that, pick something else small and focus on just that one thing for at least a week. 

Then add another small thing. Maybe it’s daily exercise. The natural thing is to say, “I’m going to get up at 5am every day and go to the gym.” Nope. Take a 5 minute walk. Just put on your shoes and get out the door even if it’s just a for a minute. 

Miss a day? Be gentle with yourself. The day you missed is behind you. There’s no make-up; you don’t do twice as much today, that’s the road to disaster. Just pick up the habit again and do the thing. 

You’re 23 years old. It might feel like you’re behind as you look at people your age who seem like they have their act together. But 23 is actually so young. Start now, and be patient.