Hey! It's a tricky situation. It obviously is best to speak to a professional if you can, but I get that you probably wanted to see what others thought first and possibly some advice
I am 18 and was diagnosed with ADHD (predominantly inattentive type) towards the end of last year (with a suspicion of 'mild ASD'). I was really relieved to know that it wasn't me just being stupid or being lazy and that there was an explanation for things. (The main concerns were concentration, focus and time management). I wasn't so sure about the ASD at the time (and I'm not diagnosed still) but I am realising now that it could be possible. I also do have anxiety and I think it's possible that it partly developed because of my undiagnosed ADHD.
I can really relate to some of the things you are saying. I have always done quite well at school, but when I did my GCSEs and even now, I knew that I didn't do as well as I could have and it's frustrating! I can be a perfectionist with my schoolwork too, and I was told that this is likely due to my ADHD and my slow processing speed. I also have a good working memory, but tend to forget simple things after a few minutes of being told. Also, I don't tend to feel any significant sensory issues - this one really can vary from person to person I think.
Some of the other symptoms, I am similar and these are common for ADHD (as I assume you know), but these can also be normal things that people struggle with too, so it's about finding that difference. If it affects you on a daily basis, and it is a struggle to deal with, then it is possible that it is ADHD (but not certain!). It is common for those who have predominantly inattentive ADHD to go undiagnosed too.
Obviously, I couldn't say whether you had either of these things or not, and it is possible that these are just normal things. But, if some of the things you mentioned seem a problem or are often difficult to deal with, then it probably is worth getting some professional advice. Since I used to do fairly well at school, sometimes I doubted whether I actually did have something like ADHD, but it has helped me understand some of the things I struggle with and helped me understand myself a little better.
Anyway, I'm not sure how much this would help you, but I thought sharing my experience may be of some use! If you have any more questions, I would be happy to help as much as I can.
(sorry for the long reply - I hope it makes sense)