Asthma is scarier than people think. No one told me it could kill me and then I found myself in the hospital in status asthma (an attack that won't stop regardless of intervention) for three days with a respiratory therapist watching me for respiratory failure. People need to know asthma can kill you. Work with your doctor, work with your meds, track your own symptoms, and know your own triggers. Get healthy otherwise and stay that way. Look for alternative therapies to work with your mainstream medical care and keep your doc in the loop if you get results with alternatives. Once your symptoms are under control start exercising(which could be walking to start, years ago I started with an eighth of a mile which is about the length along a line of five telephone poles) a little bit at a time and build up your lung capacity. Learn the "pursed lips" breathing technique to help empty your lungs of air completely. Learn the yogic "complete breath" as a way of building up your lung capacity. Every little technique added together helps.
Be your own best "doctor." I actually had an emergency room doc say to me once, "What usually works for you? If you've had asthma all your life then you know better than I do how to treat you." I'm coming from 47 years of this, so I'm pretty militant about my own care, and have learned a lot along the way. After all, it's my life we're talking about!