An 8th grade speech, cute lol. You want to spur up excitement for high school. It shouldn’t be sappy because you’ll see your classmates again after one summer. Maintain an atmosphere of positivity and encourage them to work hard these next four years to obtain their goals.
Both quotes are perfect and can be effective if used in a good manner.
One thing that is a given: some people won’t care what you have to say, so don’t get discouraged if you look out and see some people not paying attention. Just give a great speech and give it your all.
Good luck.