If by introvert you mean prospering in solitude, being the master of your own fate, seeing things differently, being an independent free spirit, an automatic recluse from the busy, meaningless world, then yes, it is okay to be an introvert.
And if by being an introvert you mean the constant state of insecurity, being the lonely outcast, constantly agitating, trying to regain a long lost connection with mankind, hopelessly trying to be something you're note, then by all means no, it is not okay to be an introvert.
:)
Seriously though, if you think it's okay, then it's okay. If you want do be more social, go ahead and do that. I used to be introverted in high school and maybe I still am at heart. But I learned to enjoy social gatherings an casual social connections just as much as meaningful conversations with close friends. I made myself go to parties and join dance clubs and what-not and I couldn't be happier for it.