Congrats on graduating! As far as the "feeling old" thing goes, it will happen more and more often the older you get.
Needles & Grooves
TenderLovingKiller®
Mather
GRADUATING FROM COLLEGE IS NOT OLD
YOU ARE OFFICIALLY AN ADULT NOW
YESTERDAY YOU WERE A CHILD
THIS IS LIKE.... THE YOUNGEST FORM OF ADULT YOU CAN POSSIBLY BE
-looks at date of birth-
-throws pen against wall-
YOU ARE OFFICIALLY AN ADULT NOW
YESTERDAY YOU WERE A CHILD
THIS IS LIKE.... THE YOUNGEST FORM OF ADULT YOU CAN POSSIBLY BE
-looks at date of birth-
-throws pen against wall-
Yer Ol' Uncle D
You calling yourself old made me laugh.
Then my laughter turned into a coughing fit.
Then I farted and fell asleep in my recliner.
You're not old.
Then my laughter turned into a coughing fit.
Then I farted and fell asleep in my recliner.
You're not old.
TCell
Congratulations!
Selaws
Congrats buddy! This is just the start!
Hollywood
Congrats kid!
AnthonyI
That's odd, I had the same reaction as @Yer Ol' Uncle D 
nolalady
Congrats!! And you aren't old until kids call you old.