  Galactic field Be stars were studied by taking into account the effects
induced by the fast rotation on their fundamental parameters. Fractional ages
$\tau/\tau\_{\rm MS}$ ($\tau\_{\rm MS}$ = time spent in the MS) against stellar
mass reveal that: a) Be stars spread over the whole interval $0<\tau/\tau\_{\rm
MS}<1$; b) the Be phenomenon in massive stars ($M>12M\_{\odot}$) is present at
smaller age ratios than for less massive stars ($M<12M\_{\odot}$); c) there is
a lack of Be stars with $M<7M\_{\odot}$ in the first half of the MS. Low mass
fast rotators ($M<7M\_{\odot}$), called Bn stars, could be "becoming" Be stars.
