Time keeping issues

So, I'm a uni student. I have lessons at the most random times and it's fucked up and pisses me off beyond belief. I've found myself, for literally the last like 10 years, arriving to things like school or uni or doctors appointments or even interviews literally, at the minimum, like an hour- two hours early. I remember turning up at school, when i was in year 10, turning up to school an hour early. School didn't start until 9am and i got there at 8 and was on my own for like 35 minutes. I've been doing this for years. I dont really know if this is an ADHD thing because i know the ADHD thing is kinda the turning up to things late deal, or at least that's what I've heard. I'm awaiting my ADHD assessment thing and am getting kinda nervous about whether i am gunna be diagnosed or not. I just want some opinions because I'm lowkey stressing about the assessment. TLDR: is turning up to places upwards of at least 2 hours early a 'symptom' of ADHD?