In all likelihood your frame has a 68mm English-threaded bottom bracket shell. It's the standard on nearly all modern bikes, and certainly on anything made by specialized.
The type of bottom bracket (square-taper, integrated, or Octalink/ISIS) and the length of its spindle depends on the crank you're using it with and the spacing of your rear hub in order to get proper chainline. If you're just replacing a current bottom bracket and the chainline is good as-is, then just get one of the same size.
I won't comment on your mental capacity because I have very little information to go on. You mught just know relatively little about bikes.