My wife asked me, if not now, when? We were both smokers, she quit a year before I did (after 23 years of smoking). It's a mind thing. It's almost like a switch that was flipped. It sounds cliche, but believe me, the decision is the hard part, once you make it, it's easy. Just do it, and don't doubt yourself. Use Champix or Zyban if you need to, but do it. What helped me is, I kept EVERYTHING the same: my routine, habits etc. And DO NOT replace your smoking with anything else. Not even mints or chewing gum or anything. Then you are just replacing one bad habit for another. Rid yourself completely.
Make no mistake, it's hard initially, but it's only for a short while. You won't be sorry. Best decision I ever made. Today it's around 6 years later, and I don't even think about it anymore.
Be like Nike. You really can.