I LOVE this phrase. It doesn't hold students up to any standards that may alienate them and it doesn't compare them to others which may humiliate them. It simply reminds them to be the best version of themselves that they can be.
I saw a poster similar to this online a while ago and was unable to find the original source so I just made one that was a bit different and a bit more fitting for my wants. I think this would be a great addition to a gallery wall of classroom expectations and inspirational quotes (or if you're like me, as a visual reminder to yourself in your office).