I think I would try both in your position. IF you get the right group and sponsor, might be ideal. IF you get the right therapist, might be ideal. But lots of people I know had to work to find the right therapist, went thru 3-4 before finding someone who was "right". And I know a few people who tried different AA meeting groups (Not OA, don't know anyone personally who has done OA) until they found the right fit.
zen and the art of weight loss, finding the true path of en-lighten-ment