Good for you! I am 25 and have been smoke free for a year in september!
I gad smoked for about 3 years, I knew I didn't want to be a 30 year old smoker, so I just quit cold turkey! It was thebest thing I could have done.
I hope my mom and brother stop some day too, but I know no one can force you, or you'll just start again.
Good luck to everyone seriously thinking of quitting