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Moving day was a family affair on Wednesday as Maria Shriver and daughters Katherine and Christina sent 18-year-old Patrick Schwarzenegger off to begin his first year at USC.

"Sent my third kid off to college today...heart-wrenching for me, so exciting for him," wrote the proud mom to her Twitter page. "I understand how blessed he is to be going and how blessed we are to be able to send him. My hat is off to all these parents and kids who work so hard to get there. "

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The three had a head start yesterday, as evidenced by a photograph Maria tweeted on Tuesday of herself and Patrick stopping for a breather after an admittedly no-fuss transition into the dorms.

"It's very different moving boys into college compared to two girls," she marveled. "So much less stuff. No matching this and that."

While everyone was all smiles on moving day, Katherine found the adjustment to be a bit of an emotional one shortly after.

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"I'm officially a cry baby!" she posted to her Twitter page. "Just said bye to @PSchwarzenegger as he goes off to college and crying already! Miss him so much!"

Patrick announced his acceptance to the university in May, which just so happens to be the alma mater of sister Katherine, who graduated this past spring.