If your thread titles is an actual question the answer is "both". Personally, you should focus on the positive, there's a lot of it. Act as young as you feel (that would be 28 or 12 for me, depending on my mood), yes, you'll feel it for a couple days afterward, more and more. Learn yoga, even if you don't practice regularly, knowing how to stretch muscle groups helps a ton when you're hurting or wake up stiff.
Use this as an excuse to indulge in snobby stuff. Older men get to shave with a double edge or throat cutter (and use nice shaving soap and brush), drink good coffee, smoke good cigars, appreciate (and NOT gulp down!) good scotch, drink copious amounts of white wine, etc. and no one will think you're eccentric anymore, just "refined":)
Pluck white hairs in your beard (if you have one) and get rid of it if you start looking your age more than you'd like. If you're single you're allowed to date pretty much anyone you want, from 20 to twice your age (though as you get older pick an actual number for your top limit, dating an 80 year old might not be that fun):)
Anyway, happy birthday, every decade has something awesome in it, and you don't have to give up all the "good stuff" of youth, either, if you like it (it makes you feel alive anyway)!
I hope someone gets you something nice and some folks who care for you spend some time with you;)