Welcome! And this show isn't for girls, next person who says that to you, just shake your head and walk away.
Hmm for me, based on who's still alive and my complete and total biased opinions to characters I like....
All kids for sure, and no elderly people. It sounds awful, but like someone else said in a previous thread, if they're trying to further the human race, then you need the healthiest, most fertile and youngest people possible. And of course, people who are specially trained in useful fields. We don't need Joe the local magician.
The entire concept is so unfortunate because any time you value someone's life over another's it's well, gross.
So for me:
1-Bellamy, even though he murdered 300 grounders he's my favourite character and he's also saved Skykru's butts more than once. Does that mean he should live over them? Probably not, since he did crappy things, but he's also young and presumably fertile.
2-Clarke...for her it goes without saying - she already has some medical experience, she's young, and she's saved everyone's lives repeatedly. Including the Grounders in the bunker, who wouldn't even know about Praimfaya if she didn't like, discover that info.
3-Raven, for the obvious reasons that she's hella smart and awesome and has also saved them all
4-Monty, ditto
5-Abby, the doctor who is presently annoying me, but is a doctor
6-Stupid Jaha because he's a stupid engineer
7-Riley
7-Just kidding, let's switch him with Jackson, who's also trained medically
8-Anyone we haven't met that isn't a dumb murderer with no skills
9-Roan's ghost
10-Helios