Jeez mate you've been smoking it for half of your life.
Be prepared to lose friends when you quit and don't be afraid to put your foot down, appropriately of course, if people tell you, "just chill out kuunt, have a bong". Those are the people that you gotta black list. It might be everyone you know.
You will have everything back that you lost from smoking but it is a massive change.
Do it. It will be worth it. Then post pics of your 600rwkw car in a couple of years!