Unless the Master's is absolutely required for the position you are seeking, you should definitely wait!
Having returned to school as an older student, I am amazed by how much more I am able to pick up from the lessons. This is based on having real life experience related to the subject matter. Additionally, no matter how much you might think you are "positive" about your career choice, it could be there are aspects of the job you are unaware of, and, once exposed to them, you may decide you made the wrong career choice. As an example, a lot of social work entails keeping records and meeting statistical performance measures, rather than actual working with clients. Sometimes it causes one to wonder if they are truly "helping people" after all.
I have seen way too many people who, upon getting their Bachelor's, go out and test the job market. They aren't able to find the perfect job with the ideal salary, so they go for their Master's. Now, when they go looking for work, they are overqualified for entry-level positions, and under-qualified for the positions they want. Why? Because they lack experience! I remember one client who received a master's in Hospital Administration. She was frustrated when she could not find a job. She said that this degree "entitled" her to a position as a hospital administrator, ignoring the fact that other applicants had both experience and education.
I highly recommend giving it at least two years before going back.
Best of luck!