Zennism

Practicing Zen without practicing any religion is not only possible, but also rather common.

Many American Zen teachers prefer their students know the basics of Buddhism, but they don't require adherence to them.

Don't feel guilty if you are a "Zennist" (a practitioner of Zen who doesn't practice the religion of Buddhism) rather than a "Buddhist."

Your spiritual path may or may not lead you to more religious involvement later.

But, to force yourself to change your beliefs isn't contingent with Zen thinking.