Is it "初めてのカヌー” or is that saying something like "It was my first canoe"?
"初めてのカヌー体験です" is probably what I'd say to emphasize the experience of canoeing instead of the canoe itself. 経験 instead of 体験 would probably be alright as well.
You can say 初めてのカヌーです for “This is my first time canoeing,” as well as, more colloquially, カヌー、初めてです。
This is an addition to the other answer.