Standard Deviation Function with Time Constraints

I think this should be a relatively simple one...

I am trying to create a rolling 2-year standard deviation formula in cell K12 in which the function will run =STDEV(IF(Y76:Y267<>0,Y76:Y267))*SQRT(12) but will only include data that is in the last 24 months. The dates are in B76:B267 and the data is in Y76::Y267.

I assume I can use the today function in the logic which I have in cell W5 to tell the formula when to begin.... Does anyone know how to do this?