Need help calculating age field but want blank if nothing is entered in DOB field

I need help figuring out how to write the formula to calculate an age on a form I'm creating, however, I want the age to display nothing if there isn't anything in Date of Birth field.

For instance:

I have a Date of Birth (DOB) field and an Age field. I want the age to calculate if there is something entered in the DOB field. If the DOB field is blank I want the Age field to be blank.

Here's what I've come up with by using this Excel Forum website, however, cannot figure out how to get the age field to be blank if nothing is in the DOB field... Currently the DOB field is blank and it is showing "114" in the Age field.

=IF(MONTH(TODAY())>MONTH(P7),YEAR(TODAY())-YEAR(P7),IF(AND(MONTH(TODAY())=MONTH(P7),DAY(TODAY())>=DAY(P7)),YEAR(TODAY())-

Thanks!!f

Perfect - thanks! But does it matter about the leap year thing? That is why the other one was so long I think...because whomever wrote it was factoring in the leap year.

Here's what Excel corrected the original formula to be:

=IF(MONTH(TODAY())>MONTH(P7),YEAR(TODAY())-YEAR(P7),IF(AND(MONTH(TODAY())=MONTH(P7),DAY(TODAY())>=DAY(P7)),YEAR(TODAY())))

When I try to modify per your suggestion I get a "too many arguments" error. Did I modify incorrectly?
=IF(P7="","",MONTH(TODAY())>MONTH(P7),YEAR(TODAY())-YEAR(P7),IF(AND(MONTH(TODAY())=MONTH(P7),DAY(TODAY())>=DAY(P7)),YEAR(TODAY())))

Appreciated. Works great - thanks! Any ideas on my other post of trying to allow people to type paragraphs in Excel and be able to edit them later and keep the formatting of Word? I think so far my best option is Text Box...but we still have to resize if the paragraph is bigger than the box...