Being a 'Big Girl' at (nearly) 33

Is it strange that I find myself retelling a breakup story and saying that I handled it 'like a big girl?' What a weird phrase, that at less than 2 weeks away from being 33 years old it rolls off my tongue without hesitation. It's a phrase you tell a six-year-old when she's having a meltdown, not a phrase to describe a long-independent, fairly rational adult. It makes me realize that if I handle a situation 'like a big girl', it probably means I don't consider myself to be a big girl all the time... maybe ever. Or is it that I am just getting so practiced at being broken up with that I am just learning how I am supposed to act?
I didn't sob uncontrollably. I didn't throw a temper tantrum. I didn't get angry and slam the door. I just stoically sat quietly and listened to why I just wasn't the one. Yet again. I quietly wiped the tears as they slid silently down my cheeks. Once again. I didn't grovel and beg him to change his mind. I know that wearing heels and perfume next time I see him won't make him doubt what he's decided.
Maybe 'acting like a big girl' is actually just accepting resignation. You've lost. The race is over, and you didn't win. Nothing you can do can change that. No arguing with a referee. No whining about it not being fair. There is no asking for a do-over. When you've put your heart and soul into that race, projected your wishes and dreams onto it's hopeful outcome, it's really hard to accept. You're exausted and drained and utterly defeated. You can't fathom lacing up your shoes to do it again. And you have a splitting headache from the muscle tension in your forehead as you tried to keep from crying... compounded with the dehydration that comes with the floodgates opening as soon as he leaves and you can't stop crying.
But after a full day of welling up approximately every eight minutes, I think I've cleared the system. I've still got that pounding headache. I still have that dull heartache. But the feelings of desperation have faded. The irrational thoughts of never finding someone have gone back underground. The swelling around my eyes has gone down and with the flush in my cheeks, I actually looked pretty when I saw myself in the mirror a few minutes ago. I hope sleep will wash away the rest of the sadness and I can start tomorrow fresh. Because, isn't that what big girls are supposed to do?