SOLVED. YA novel about a girl who grew up on Mars with only her uncle until a colony ship arrives from Earth. [s]

[Elspeth]

I read this in the early 00's. It was a young adult book about this girl who grew up on Mars with only her uncle (I think). A colony ship from Earth arrives when she's a teenager and she falls in love with a boy from the ship. But her uncle/guardian has told her that she needs to wear a spacesuit whenever she's around the people from Earth. She doesn't understand why this is or why the people from Earth always wear spacesuits. Then she takes her helmet off in front of the boy she likes and he is horrified and runs away from her. She then finds out that her guardian wasn't really related to her, he was a scientist who experimented on her as a baby to make her able to survive on Mars and gave her lizard-like skin and that's what disgusted the boy from Earth. In the end she realised there was no one else like her and no regular human would ever love her so she goes off to spend the rest of her life alone on Mars.

Thanks for any suggestions anyone has! This one has been bothering me for years.

[[deleted user]]

Could it be The Keeper of the Isis Light? (Not set on Mars, but the other details sounds exactly the same.)

[Elspeth]

YES that's it! For some reason I remembered it as being Mars, but yes that is definitely it.

And now I know that it's part of a trilogy too! Thank you so much!