Yes it is normal to wait for 6 months , or more maybe because it is risky and if you want to gain you have to be patient and wait maybe 1 year , you won't know what will be after 1 year , you can be rich???
I think it's okay if you're sure that you will be paid. If not... after 2 weeks of waiting, I would unsubscribe from the project and go on working without even turning around
