As far as I know you can enjoy 1 year of  OPT after completion each level of your education i.e. you will get 1 year OPT after completing Associate degree, 1 year after Bachelor's degree and so on. If you decide to have 2 Bachelor's Degrees still you are entitled to get only 1 year of OPT. I guess it will help. If you are planning to proceed your immigration journey( working visa, green  card) with associate degree, it might not work well. Please always consult with immigration lawyers or visit official sites to make your decision. I am giving this info on the basis of what I have heard...
Regards,