I enjoy judo but don't want to enter the next grading. How do I explain that without sounding uncommitted?

The instructor put a grading form beside my bag and said, "You're ready. Don't hold yourself back." I'd just told him that training twice a week was enough for me this term.

I like learning and practising. The next grading would cost $65 and involve an extra session I can't easily fit around work. More than that, I don't currently want an exam to become the reason I'm turning up. When I joined, the instructor said I could train without rushing through grades.

He's been encouraging rather than threatening. He says seeing adults progress helps the newer members, and I worry that declining will look like I don't value his teaching. I haven't said that to him because it sounds a bit grand for a club evening.

Would you give the practical reasons, explain that the grading goal itself doesn't appeal right now, or simply decline this one and see how next term feels? I want to keep learning without promising a date just to end the conversation.