being without accomplishment at 20 is perfectly acceptable. even at 25. it's once you creep toward 30 with nothing to show for it that things start to get hairy. i turned 27 and decided to really forge ahead. and so i do. forge.
i have stopped making plans on my birthday. it always ends up making things a giant suck if i do. i like to spend the day by myself, treating my brain to reading a good book, going for a walk, maybe seeing a movie. at some point in the evening, i might call a close friend to go out for a drink.
keeping things lo-key will yield a much happier birthday, i've found.