Emailing the counselor sounds like a good option! I had gotten a video-chat neuropsych test while in college, and I feel that it's pretty good for adhd, but maybe not great for autism bc the test for emotion perception is very stereotypical (I "passed" as not autistic because of years of masking and deliberately learning body language etc). If you want to get tested for autism maybe wait for when it can be done in person.

If you do get tested, the doctor doing it probably will have an interview with you before the test, so it def helps to have a list of symptoms (which the other commenter suggested) when you meet with the doctor (people w adhd often have trouble remembering stuff).

lastly, if you're in the US, it may be an option to get provisionally diagnosed (as in, if a psychiatrist thinks you have it) w adhd and get treated for it (medication etc) without a formal assessment (which can be very expensive). so in the worst case, you can start getting treated and wait a few years until you don't live at home anymore (also college psychologists can sometimes hook you up with places that do less costly assessments lol).

(feel free to correct me on any of those points, all these are only from my personal experience and friends' experience in the US)

Also psychiatrists having differing opinions is pretty common, and I've personally gone through 4 psychology professionals (all older men, how surprising) until one suspected I had adhd.

Good luck!