Go for it. "I'm unstoppable!" That worked for me.
What tipped me over was my closest cousin who shared my birthday with but was 3 years younger than me, died a few years back. He was 36. C started in his lungs then spread to his spine. Last days were fubar beyond recognition. I still miss smoking but those last days are a horrific image in my mind.
Bizzarly - shortly after he passed on - I bought my first mtb (I still dont know why?) since I was 16. Now Im addicted to somehthing else - more exepensive more addictive (more dangerous?) but life expectancy is slightly better
My only advice - find others wanting to quit - especially guys. Talk it through with them. I think NHS do this but its better if you know them.
Also, as you're on a cycling site - your ability to climb will increase exponentaiiy! Honestly - a smoker on a £10,000 carbon trendy cult whatis bike will never ever EVER get up a hill as quick as me as on a post bike. With a camel in the front basket. And a sink dragging off the back. And the draggiest tyres in the world. And a ships anchor ....
As you can tell - I'm probably willing to help / encourage. If you need a challenge (and can supply the camel) I'm up for it.
BTW my crutch thru all of this was a very expensive humidor full of cigars that now I will never smoke. We all need some sort of escape / crutch.
Ronan