Hmmm aquiring yourself to stay young?...Can you say "immortality"!? But that's probably something that Andalites thought about and got rid of while inventing the Morphing Cube
You can say it, but you wouldn't have it, you would at best double your lifespan. Well, is it ever stated if their normal bodies age when they are in morph? If not, I suppose you could morph younger self, demorph every 2 hours for 1 minute, and live longer that way, but it's pretty risky.