This person you confided in does not seem to have any particular expertise in ADHD, is that correct? Certainly the things they said aren’t true of ADHD. There are a lot of misconceptions about the disorder, and its name doesn’t help. It’s not just about attention or hyperactivity. Fundamentally, it’s about self-control. So, some things you’ll be very good at, others you won’t have a handle on. ADHD doesn’t mean you won’t be functional in your life, it just means you aren’t in much control over what is functional and what is not.
Get yourself tested, see a doctor.