In Death of a Salesman, how old are Biff and Happy during their conversation in the bedroom? Does it take place in the past or present?

The conversation between Biff and Happy that takes place
in their bedroom is found in the beginning of the play. The time is the present. Willie
has just returned home, tired and confused; Biff and Happy listen to their parents'
conversation in the next room. Biff is 34 years old; Happy is 32. These facts are
established directly and indirectly. Willie makes a reference to Biff's being 34;
Miller's author notes say that Biff is two years older than his
brother.