 But not your heart away;
Give pearls away and rubies
 But keep your fancy free."
But I was one-and-twenty,
 No use to talk to me.

When I was one-and-twenty
 I heard him say again,
"The heart out of the bosom
 Was never given in vain;
'Tis paid with sighs a plenty
 And sold for endless rue."
And I am two-and-twenty,
 And oh, 'tis true, 'tis true.
Not literally true! “When I Was One-and-Twenty” is a  dramatic monologue  from the collection  A Shropshire Lad  (1896), published when Housman was 37 years old. However, it’s possible the poet is adopting the voice/stance of his younger self. 

When I Was One-and-Twenty