I am 38 years old. I have smoked since I was 18 years oldand I quit smoking one day ago. Chantix helped me stop but is it too late for my lungs to heal?

Not too late! Congratulations! our bodies have a remarkable ability to heal. A diet rich in fruits and vegetables (ideally organic) will help speed the healing process. A good multivitamin may help as well. Here is a good timetable of the healing process after one quits: http://whyquit.Com/whyquit/a_benefits_time_table.Html.
Never too late.. Congratulations! your blood pressure will start to return towards normal within 15 minutes, your heart rate will respond within days. Your lung function can take longer to improve, it has to heal, and some of the changes may be permanent, but at your age hopefully mild. Your risk for lung cancer drops to that of the general population somewhere between 5-10 years after quitting. Hang in there!
Smoking . From your history, no it is not too late. Keep up the good work.