Whilst reading this site, you might be just a year or two away from living it. In order to make that happen, you have to act now.
Get a health check up. You will need good arteries for your quest and an overall healthy body. It's too late to do the checkup right before the climb. You might have to work on your health for a while to get everything in shape.
Check your cholesterol. It will take about 3 months to reverse bad levels. Fatty, clogged up arteries are the last thing you need on Everest. You'll get frostbite in no time. Check yourself for Asthma, since the cold, dry air might trigger it (although it cures it at times!).
It is wise to check your heart, lungs and brain, since the blood will be thick and put pressure on weak veins. Good circulation is essential - quit tobacco, it tightens the arteries. Lower your blood pressure if needed.
Your condition today doesn't mean that you can't climb tomorrow - as long as you do something about it! And you know well what that is - quit the bottle, the smoke, the fat and start working out.
If you are in a really poor condition, you will need around 2 years to be truly fit for fight. After Everest, you can return to the old lazy you. Chances are however that by then you will have discovered a whole new world of fun and will never want to go back.