Birthday gift or indie film?

That's a tough decision! Personally, if the trip hasn't been paid for yet, I would work on the film. Any line of work is difficult to get into at the moment and obviously the film industry is particularly competitive, so any experience would be really valuable if you want to pursue it as a career. You also might meet people during the shoot that could recommend you to another filmmaker or know of work in LA for when you move there. The trip is a lovely gift and the East Coast is beautiful at any time of year, but it will always be there for you to visit in the future. Hope that helps.