Date excel userform's textbox

Hello,
i have a problem in excel userform's textbox(txtDateofBirth)
if date of birth is between 01/01/1981 to 01/01/1991 then msgbox show "Adult"
and if date of birth is before 01/01/1981 then msgbox show "Too Old" & after 01/01/1991 then then msgbox show "Too Young"

can anyone solve my problem please.

AKS