Plagiarism in a essay?

Basically, in an admission essay of 250 words I used a quote from the movie kung fu panda… being more specific, this one: “Yesterday’s the past, tomorrow’s the future, but today is a gift. That’s why it’s called the present.” I pretty much rephrased it, the only part that is truly identical is the final phrase. I used this quote to try to express something, the main point of the essay, but I completely forgot to say that this phrase was from a movie – at least the idea behind it. Will it be considered plagiarism??? should I e-mail the university? any chances that it might affect my admission to other universities too??

I feel like that phrase is used so much it’s basically common knowledge. Wouldn’t worry about it.