With all due respect, oogaboo, your dissertation here is sort of coming off as a rant (That's the way I see it, anyway). Most of us on the GOF agree that the LBT studios have made some major blunders in the movies and TV episodes (indeed in many cases it seems they just didn't care enough to rewatch the older movies to ensure continuity), and find many of them irritating, but the majority of us also feel that the series has enough good points that should not be denigrated as a whole for such mistakes. Your opinions are respected; if you don't like the sequels or the TV series, that's fine, but the way you are wording your views here just makes it sound like you are complaining about how the series was handled, and may be upsetting to some members, even if you did not intend any offense.
Why am I constantly wondering how old they are? Because this is for an audience that simply won't care. Anybody that does care and have watched the first movie are pretty much dinosaurs themselves. I on the other hand, am not going to continue wasting my time figuring out their TRUE age unless the guys that created the characters tell me.
Forgive me, but what does this mean? I don't want to jump to conclusions, and know full well that I may be misinterpreting you, but this sounds a little insulting to the LBT fans who are curious about what the gang's ages are, and spend time discussing the subject. (What do you mean by calling them "dinosaurs"? In the sense of being ancient, oblivious, outdated, and doomed?) Again, it's fine if you disagree, but please try not to offend those who may have different opinions.
I must emphasize that I do NOT want to cause a dispute, and I apologize if I have misunderstood you. But even if that is the case, please try to be a little more tactful in stating your opinions in the future. Thank you.
I always saw Littlefoot and the gang as being around grade school age. So my guess is: Littlefoot, Ali, Cera, and Ducky are probably about eight. Petrie's behavior and poor grammar seem to suggest that he may be younger than the aforementioned three. However it's really difficult to say because we never see him hatch. Therefore he could be the oldest, or he could be the youngest after Spike. Anyway, my guess is that he's around seven. Spike is of course, the youngest, so I assume that he's either six or five.
Personally, I've always interpreted Ducky as being younger than Littlefoot and Cera (which would have meant that either the swimmer shown hatching at the beginning of the first LBT wasn't Ducky, or the hatchings of the three characters were shown out of sequence). As for Petrie, like you said, it could go either way. In the fifth movie and beyond, his squeakier voice makes him sound younger than the others, in my opinion, but in the earlier movies I kinda thought he sounded older.
Just an observation about your guesses of the gang's ages: if Spike were to be five years old at any point in the series, the other members of the gang would have had to have only been two or three at the time of the first movie. It's possible that the dinosaurs age differently from humans, so your guess could still be accurate. At least two years must have passed since the first LBT and the sixth (in order for the Great Valley to have recovered from the events of III and V), so we know that the gang has aged more than that during the series.
I think I may be dragging the discussion off topic here.

Here's
Here's the thread for discussing the gang's ages, if anyone's interested.