One example of a quote about teenage love is "Talk not of wasted affection; affection never was wasted," by Henry Wadsworth Longfellow. Another example is "The consciousness of loving and being loved brings a warmth and a richness to life that nothing else can bring," by Oscar Wilde.
The quote by Longfellow implies that expressing affection is always worthwhile even if the relationship doesn't last. This quote is applicable to young lovers because many young relationships do not last long. Longfellow was an American poet and teacher in the 1800s. He was the first person to translate "The Divine Comedy" by Dante Alighieri.