Can you outgrow asthma? I.E. Have it as a kid, then completely be free of asthma as an adult? If so, how does that work? Thank you.

Not really... Asthma is a chronic, incurable disease. However, you can have long, symptom-free intervals between exacerbations. Sometimes, these intervals can even last for years! but, you can develop an asthma exacerbation at any time, even after many symptom-free years so your asthma is really not gone, just in remission! avoiding known triggers and avoiding smoking can lessen your chances of an acute episode.
Chronic illness . Asthma changes over your lifetime and it is a chronic disease with various triggers.
You can't . It's a chronic inflammatory condition. It will not totally go away.