[Auswandererkartei Bremen (International Refugee Organization-Kartei)] do_9wMRHovPweDSLWAg97CAM

Her religion entry in the passenger list reads „7 TA.“, which would support your assumption.
(also see Wikipedia; with abbreviation STA = Siebenten-Tags-Adventisten)

(In this card there seems to be a typo: I read „7 ga“ (not da, which would probably be correct, not ad… ).
Maybe you would like to check this in your comments? ;- )