Sure thing, as long as your duffel will definitely fit underneath the seat in front you. If it's a large duffel, and you have a garment bag that won't fit beneath the seat, you might be asked to check one or the other.
I was reading this conversation and thought I would chime in. I'm a soon-to-be-retired teacher and would love to be a flight attendant after I retire (I'm tetiring early). Would you please send me the qualifications as well?
This sounds like fun! Can you send me an email. Thanks.