O MISTRESS mine, where are you roaming?
O, stay and hear! your true love 's coming,
   That can sing both high and low:
Trip no further, pretty sweeting;
Journeys end in lovers meeting,
   Every wise man's son doth know.

What is love? 'tis not hereafter;
Present mirth hath present laughter;
   What 's to come is still unsure:
In delay there lies no plenty;
Then come kiss me, sweet-and-twenty!
   Youth 's a stuff will not endure.

William Shakespeare

http://www.poemhunter.com/poem/sweet-and-twenty/