It will be hard for you to get in big 4 unless you know someone over there. They like to hire college graduates or people with experiences. Tax maybe better than Audit. However, higher level position in industry doesn't necessary require big 4 experiences even it is on job posting. I think industry experience is always more important than big 4 experience. Managers who come from big 4 are too much technical and less practical experience in a "real world". Gook luck.