  We present a selfconsistent model for stellar turbulent convection which is
similar in spirit to the CM model (Canuto \& Mazzitelli 1991) since it accounts
for the full spectrum of the turbulent eddies rather than only one eddy, as
done in the mixing length theory (MLT). The model differs from the CM model in
the treatment of the rate of energy input $n_s(k)$ from the source that
generates the turbulence. In the present model, $n_s(k)$ is controlled by both
the {\it source} and {\it the turbulence} it ultimately generates, thus
ensuring a selfconsistent modeling of the turbulence. This improves the CM
model in which $n_s(k)$ was taken to be equal to the growth rate of the {\it
linear} unstable convective modes.
  However, since the formulation of a selfconsistent treatment is far from
simple, we were forced to use a representation of the nonlinear interactions
less complete than the one in the CM model. The ensuing equations were solved
numerically for a wide range of convective efficiencies. The results are the
convective flux, the mean square turbulent velocity, the root mean squared
turbulent pressure and the turbulent viscosity.
  We implemented the model in the ATON stellar structure code and computed the
evolution of a solar model. The results are generally similar to those of the
CM model and thus quite different from the MLT. The present model requires a
smaller overshoot into the upper radiative zone than does the CM model, in
accord with recent empirical estimates. Application to POP II stars and
comparison with the very metal-poor globular cluster M68 yields an age in the
range $11\div 12$ Gyr. This is somewhat younger than the CM age, which in turn
is younger than the corresponding MLT age, a result of possible cosmological
interest.
