I do this all the time. Also wearing headphones and listening to music to avoid people trying to talk to you once you arrive somewhere, so they won’t distract you from your plans.
I’m usually even 30-45 mins earlier because my problem is rather what to do with that time before having an appointment. I will just sit at home and get nothing done until it’s time to get ready and leave, so I’m better off leaving the house. Take a stroll in a nearby park (if I’m familiar with the area - it’s great to calm down), or I’ll get some food and eat (if I feel comfortable) and just sit down and read as I’ve arrived.
Oh well, there’s those other days as well where I just forget time and am in a rush to get to places and forget half the things I need. Definitely prefer the first version…
NOOO MOOMIIINNnNnn!!!