"I'll miss my friends, but I feel like I'm ready to go," said Polanen, Castilleja's student body president, who also is active in the theater program.
Following a road trip with her family to Oregon and ideally finally getting her driver's license this summer, Polanen heads to Harvard University in the fall.
Though undecided on a major, she envisions a career in media or film production.
"Directing and producing and writing — that would be ideal for me.
"I'm pretty open. I know things aren't going to turn out as I plan."
Polanen has been in three productions just this past year: "Twelfth Night"; a pantomime version of "Aladdin"; and "Quilters," a musical about pioneer women and life on the prairie.
Born in Berkeley, Polanen spent much of her childhood living in Amsterdam and looks forward to the more urban environment of Cambridge.
She also relishes the prospect of "meeting people with whom I don't agree.
"Everyone here seems to have a similar set of values and opinions. Everyone here is very liberal. You don't tend to meet that many people with very strong conservative values.
"I feel like being in a more diverse community will be more interesting, and prepare me for endeavors beyond college."
Polanen isn't exactly sure where technology will lead her generation, but knows that things will be different.
"'The world is flat' — that's such a good way of describing it.
"Everyone is coming onto this equal playing field. It's so much easier to communicate with everyone else. You don't necessarily have to be the best in your area; you have to be the best in the world to succeed.
"You'll also be able to get input from all over the world, and maybe we'll be able to improve whatever it is we're trying to do because we're accommodating more and different types of people."
She wonders whether social media will "encourage nationalistic feelings, or break them down.
"Will people feel more attached to their culture because it's so much easier to access and learn about culture, or will it blend us all together?
"It's interesting to think about how that will turn out. It could be either of those two extremes."