SOLVED. YA/juv fic sci fi book about three kids travelling to different planets/times/dimensions, part of a series [s]

[Elizabeth]

I read the book around 2006, but it might have been published in the 90's. I don't remember much, but i think it is the second or third in a series, since there was talk of two of the protagonists already having gone on an adventure (i think something that involved whales). I only remember two other things: One of the protagonists gets kind of philosophical and talks about how aliens call their own planets "earth" and not the weird sci-fi names we give them. Another protagonist essentially witnesses the genesis of life on an alien planet. The creatures are kind of like turtles? And she basically becomes their God and names all of them, naming some of them after the Star Trek bridge crew.
I wish I had more plot points, but I was probably 10 when I read this, so I don't remember much! Please help!

[Sue]

Very detailed description! This is 'High Wizardry' the third book in the Young Wizards series by Diane Duane. The girl, Dairine, is the sister of Nita, who with her friend Kit Rodriguez is one of the protagonists of the first 2 books; 'So You Want to be a Wizard' and 'Deep Wizardry' (with the whales.) There are 10 books in the series so far. The species Dairine watches being 'born' is a silicon lifeform.

[Elizabeth]

that's it! thank you so much :)