If it makes you feel better, you are now legally allowed to do things at your age that you were restricted from doing when you were 17 or younger.
But dont take up smoking, that stuff will mess with you, I've had several chainsmoker family members die from that stuff, so I'd heavily advise you to not take that up.
Also, if you're looking for fun, theres tons of games coming out this year.
Go get some cake. Cake is love. Cake is life.
Happy birthday!