Hello. blood pressure based on various age groups

Blessing and peace to everyone.
I am very new to codes and formulas and hope to learn as much as possible here.
I work with disadvantaged people of all ages and been trying to find a way to document their blood Pressure based on their age in excel to e-mail to their Dr.'s. I already have a blood pressure program that calculates normal and hypertension ranges. Basically, there needs to be a drop down box that has the age ranges like (16-21) which I can do. Next I need a (IF?) formula that says, if the person is between 16-21, their normal blood pressure range should be, 124 78 for example. I know this is probably very simple; but after several days of trying to figure it out, I am at a loss. Thank in advance.