I've met loads of travelers with dogs. they all seem to agree that your life gets somewhat complicated by the fact that you have one (with varying degrees depending on how well educated / misbehaved your dog is) but on the other hand I never met anybody that would drop the dog if they had a chance, as they are great road companions. they protect you, give you company and unconditional love. 3 things pretty hard to find right?.
About jobs, ive been working on the typical jobs a seasoned traveler ends up depending on and ive shared spaces with traveler dogs most of the time. My guess is that its gonna be frustrating sometimes but since you are not the only one you'll find the way by trying and asking around.
One of the things that get the most complicated is transport. If you ride freight and walk, that should be fine, hitchhiking might get a bit more complicated but works nevertheless. Buses, airplanes, etc can get harder / expensive but not impossible. I know in Canada, USA and Europe there are tags you can get for some money that will make yours a service dog and that would allow you to go on buses, planes, trains, etc. but once you're out of such countries its all about smooth talking your way into transport.
About age... i've seen some really old ones. recently i traveled quite extensively with a friend who has the same kind of dog you have now. he was 12, now he is 13 and still going around. of course he is dog-senile and his hips are fucked so my friend's lifestyle has to go around his dog's age but if you have been 13 years with a dog you love that will come out naturally.
make sure not to feed him shit , that will make the dogs life (and yours by association) a living hell later on. German shepherds develop lots of problems in their hips and bone structure, so make sure the dog runs and jumps a lot trough life and gets a good diet, otherwise those issues will come up early in life and you'll end up hauling a disabled 7 year old. remember: your dog was bred to be chasing cattle constantly 7 days a week 365 days a year non stop, if it doesn't get to run and have mental challenging situations it will grow crazy grumpy and weak.
Have a great ife with your new companion. not to be dog racist, but german shepherds are great dogs, they are so intelligent that you'll find oftentimes your dog is smarter than some people.
