It's really not customary to give yourself a title, esp. one of B.A.
It would be different if it was a career title, such as LSW or CPA . A degree in and of itself indicates completion of a field of education, and not the actual experience of a profession. It would come across as arrogant, pompous, etc.
Just use your name, fill in all the blanks. It will ask you about your education. On any letters you have to write, such as if you have to write a letter of interest or something similar, you could write
"By the beginning of the Fall 2019 semester, I will have completed my undergraduate studies, earning a Bachelor of Arts in Psychology. " or something like that. If you have interned or done special research, you will want to play that up.
I have used my BA in my signature, esp. when writing to schools
B.A, Sociology, 1983
Texas State University
Hope this helps!