COUNT.IF does apply here?

I was asked to help a student with the basics of Excel. It's embarrasing but I couldn't solve this:

There is a list of 69 students, males and females, (M and F) of varying ages. I am asked to tell in a cell, the number of females older than 17.

I tried to use the function COUNT.IF, as follows:

=COUNT.IF(C2:C70;AND(E2:E70="F";D270>17))

range C2:C70 with the names (I expect the function to count over this range's cells)
range D2: D70 with the ages
range E2:E70 with F or M

Please note that I tried to translate the functions that in Spanish show up as (longtime I don't use an English version of Excel):

CONTAR.SI (conditional counting)
Y (direct equivalent of a boolean AND)

What I am doing wrong?

The usual (useless) disclaimer "I used to be profficient in this..." also applies....