You will have the same opportunities as every other person, and then some! Agencies have EEO criteria they are striving to meet. Many have shortages of women, and African Americans. Although you may not want to be hired because of these factors, the truth is, as you already know, it is something that will work in your favor. However, there are certain threshold requirements you must meet, pertaining to things such as GPA, physical conditioning, vision, hearing, criminal background, etc. So long as you meet these criteria, you should have no trouble getting a position as a patrol officer, probation officer, detention officer, etc - all positions that don't have enough women.
Where you go from there is up to you: investigations, training, administration, K9, law school, crime victim advocate, etc. The key is to get your foot in the door, see what appeals to you, and move on from there. My recommendation would be to do two years as a patrol officer, and then re-evaluate your career. That is because it takes about two years to get good as an officer - to be exposed to a good mix of calls, and learn to handle yourself in tense situations.
Best of luck!!