Yep, she is broody! You are right. Now, if you want to break her broodiness, then you should put her in a cage with food and water ONLY--no bedding or anything extra. She'll have to be caged for about three days, and you can then let her out to see what she does. If she's still broody, put her back in the cage for a few more days.
I have a BCM hen who is also broody. I haven't broken her and she's been that way for a few months now. Broodiness can last a long time.
Sharon