Okay, first off, school counselors, are awesome, theyre usually really chill, and theyre sworn to confidentiality as soon as you go into their office. (because it sounds like you want to keep this pretty low right now, you're probably right about going to them) If you don't need to make an appointment, and can just head into their office whenever, you can say something along the lines of what you asked in your above question: "Hey, Im ---. Can I come in for a few minutes, I have a quick question."
If they say sure, just keep going, (they'll prob have you go in their office and shut the door or whatnot, just out of habit)"So I've been looking [online?] and realized that I have a lot of symptoms for ADHD, and was wondering if you had anyway to get me tested. I've been wondering for a while, but want to keep it pretty low key."If you have to set up an appointment, no sweat, lots of counselors like to keep things organized. Just make a time (during your free period/right after school are usually easiest for students? I'm assuming you're in jr or high school) and say basically the same thing as above.
Because there are tons of ways to test for ADHD, and lots of them involve learning about your daily lifestyle/habits, so know going into this, you may want to include your parents/whoever you live with. Also, you're gc may not be able to personally diagnose you, but can tell you who can! (this paragraph is very what-if-y)
Ugh sorry that was so longggg
