I've been asthmatic ever since I was born. I'm turning 19 years old. My peak flow on a daily basis is 200. The highest I've ever gotten in my life so far is 300. I take a special symbicort inhaler as I land in hospital every year between September and December time.
It can be cured yes. In my instant it's not likely. But from what I know (which is a lot as I've had so many issues with it) I think you could get rid of it.
Try taking your preventer (brown inhaler) twice in the morning once you wake up and twice before you sleep.
Try taking 2 puffs of your reliever (blue inhaler) before you start excercising at the gym.
Try not to over do it at the gym. Take baby steps before working extremely hard at the gym.
Control your diet take a lot of fluids (water) and maintain when you take your reliever (blue inhaler) if you take it too much your body is bound to just rely on it. I'm not saying try living with out it. But take it if it is really nesserary and always before a physical activity such as a long run or jog, any sport games.
Be motivated in helping yourself and stay postitive. With willpower and a postitive mind I believe you can do it. It isn't impossible it's happen many times.
I know I didn't say much but I hope this helped at all :)