Calculating New Date And Returning Dates Within A Range

I am tring to add a number of years to a dob. I'm doing this by adding my
date+years*365.26 I get a string of numbers. I then convert the number in
the next column to actual date again. I'm getting the correct date. I've tried unsuccesfully to use the dateadd function.Now I want my criteria on that column to allow me to return only date in a given to from period of my choosing. I want to determine the date range each time I run the query.

An example would be:

DOB age date I need to follow up
5/15/1935 + 75 = 5/15/2005

Then I request dates between 4/1/05 and 5/30/05 and this date is returned.


I've tried the between_and functions but nothing is returned. I'm guessing it's because the column is still a calculation and not a true date.

I've tried: Adding a column to my query to convert the number string back to
date format (criteria failed to return a result). Adding a second column
that ='s my converted number to date column (criteria failed to return a
result)
And I've tried the make table query and then run another query from the new table. I can't seemto make this happen. I think it's not recognizing my data as a date because it isn't returning any data.
Is ther an easier way to: Add a number of years to a date and have it return
a date and not the number string?
If not is there a better way to convert the string to a date?
Is there a way to get my criteria to recognize the date and return date
between my begin and end dates?

Thanks