I'm 42...and still waiting for my hubby to retire from the military before I can start seriously adding snakes to my collection. (Likely retirement could be anywhere 5-10 years from now, depending on how his career continues) Needless to say, I won't be starting any serious collecting until well into "middle age." And I don't think there's anything wrong with that at all.
It doesn't hurt, though, to make plans for a day when you can no longer reasonably take care of your snake....whether that is due to old age (we should all be so lucky!) or to some other life-changing event before that.
I don't see anything wrong with putting a paragraph in your will about your snakes (and all pets) and saying what you would like to have happen to them. Make sure that you choose someone to care for them or find them new homes that doesn't have a problem handling snakes or other animals, though. Also, getting to know folks in the herping community....through Internet sites like this, or through local herping clubs....and when the time comes, you'll be able to find good homes for your animals.
In the meantime....enjoy! Life's too unpredictable to let old-age worries deter us from fulfilling our dreams now!