Someone said third person is better for new writers? Interesting.

As for the question, it depends more on the story. First person is a popular pov in YA in general (not just sci-fi ya) but there are also many great books in third person. I would suggest what goes best with your individual story and what you're more comfortable writing. I'm surprised by the comment that person made because from what I have seen in YA writer networks and even the writing on here, First Person is very popular, in new writers and ones who aren't so new. Both can produce good stories (first and third person) depending on how they are handled.

Personally, I'm not a fan of first person. It's an individual preference thing. To me, it's harder for me to be engaged and interested in the main character in first person. And it's also riskier because if I can't relate to the main character and I'm stuck in their head the whole novel, can cause problems. Whereas, if a character is a little annoying in third person, at least I have a little space. I'm not in their head watching them drool over some guy when they should be figuring out who is trying to hurt them... I'm also not very good at writing first person. So, I write third person limited for my YA novels.