Aging accuracy in Mario's world never really shall I say, was great.
I mean in Partners in Time, the ages of baby version of the Bros, Bowser, and Peach were like this:
Mario and Luigi: 2-3 years old
Bowser: At least 6 since he spoke in complete setences
Peach: Less than 10 months since she never walked.
Now in Yoshi Island's II, it basically says the 6 of the main 8 are practically the same age. I know Mario doesn't nessacry has a canon but c'mon, draw the line somewhere.
Now that I think about it, is present-day Yoshi the same Yoshi that helped Baby Mario all those years ago? I'm leaning towards no but I would like to hear more opinions.