As written, yes this would work. However, it's very possible that a Dragon would abhor being subjected to a curse, even one that makes him stronger. He might resist it or seek a magical cure. He might grow to resent the PC's for placing a curse on him and seek revenge.
Another unwritten limiter could be that while the Dragon ages and grows as expected, his supernatural abilities would not grow to match. Physically, the Dragon might resemble a Great Wyrm of its kind, but it's DR, SLA's, Sorcerer spells known, Breath Weapon, and other age category-related powers are still that of an Adult of its kind (or whatever age category it started out as a few years ago.
While a Great Wyrm Gold Dragon (just as an example) might be the epitome of valor and good, handing such powers to an adolescent Gold Dragon without giving it a millennium to learn restraint, or even understand his powers, could result in a more malicious dragon. Maybe with so much power and so little wisdom and real-world experience, what would have grown into a LG creature could grow into a CN creature - one who doesn't feel like helping the PC's now that it can do whatever it wants, even if it was on board with this plan before the Curse was applied.
So basically this should work as intended, but it's clearly a loophole in the curse and it wouldn't be a terrible idea to include a reason (such as one of the above) why not every Dragon - especially more morally ambiguous ones - has simply put this curse on themselves, resulting in a world of exclusively Great Wyrm dragons.
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Generally magical ageing effects only work on the physic of a creature, not the mind, so you would have a dragon with a shortened lifespan, the mind (and so the spellcasting abilities) of a younger dragon and a body that has growth without the time to learn how to use it.
In my opinion, when compared to a normal dragon of his new age, it would have a lowered BAB, lowered skills and the spellcasting abilities of its original form. After realizing what kind of cripple it is, it will be way less friendly with the PCs (special circumstances can and will change that).
Where that in the glossary, where you find this course, it say: "While some curses cause a progressive deterioration, others inflict a static penalty from the moment they are contracted, neither fading over time nor growing worse." Getting a benefit from something that is meant to cause harm should be looked with some distrust. Generally it has hidden drawback.