As you've said below, some treat it like a big hoo-haa, some
don't. 21 is a turning of age, & since you're making a big
hoo-haa about turning 21, then don't you think it also represents
GAINING a certain MATURITY in thought?
Your boyfriend has specially taken the day off from a hectic
working schedule, booked a table at a restaurant, & taken the
trouble to invite your friend. It's highly likely he's gonna pay
for your friend's company because he hoped you would enjoy your
birthday!
What more can you want? 
GEEZ.
FeowFeow