My therapist told me it is imposible to have ADHD and study all the material for an exam in one night

So, I've been thinking for almost three years now that maybe I have ADHD, I have a severe lack of focus and I cannot study it is a living hell for me.

I've always did great in school but nevet touched a single book bc I couldn't unless it was somehow interesting , now I'm in college and it is the first time I actually had to grab a book, I've only read what draws my attention but there is a lot of material I haven't read. I also have a thing with tasks and struggle to acomplish any of them, domestic or academic I just cannot seem to be able to start/finish anything and it is exahusting.

So, with this points and others that I will not clarify bc I do not wanna make this that long, I went and found a therapist, I've told them everything, from my lack of focus and organization and risk-taking behaviour. I also wanna clarify I do not wanna diagnose myself I'm open to being wrong ab this and turning out to be just normal "college lack of focus".

I told them ab my different hobbies and interests, my difficulties in my everyday life, yada yada. Today we were talking about college and I told her that for a final exam I prepared everything and one night in a rush and got a passing grade(7/10) and she inmediatly told me that it wasn't possible to do that if I had adhd, she also told me that I wouldn't be able to stick to a job If I had it. Wich doesn't go well with all the data I read about the disorder, it is true that It's hard to stick to a job, but I thought that procrastinating and doing everything in a night was a very common experience between y'all.

I think I will stick to this therapist and try to follow her advice, if it fails at least I will be with less doubts ab it.

what do you all think?