Interesting puzzle. You need to make sure that all the records pertain to just one woman named Beulah, which I think they do.
I think she was born in 1913.
I originally thought 1914 was most likely, but this is impossible if her brother Henry was born on 9 September 1914.
She started lying about her age when she got married 1929 to James Mahoney and gave her age as 18 when she was really only 16. The 1920 census says she was age 6. The 1930 census says she was 17 (her husband James is called nephew of the head of house hold and she is called niece - another lie), When she marries for a second time in Feb. 1932 to Walter Timmons, she is still only 18 years old.
When she married the 64 yo Howard Lee Smith she gave her age as 73 (to make herself younger again?).
At least that is what I got with some quick poking around. I do think she lied about her age depending on the circumstances. The most trustworthy date is the 1920 census which says she was aged 6 in February 1920.