You get a sponsorship because they want someone reppin their company hard, and they want people to be like "wow that kids sick, maybe i should get some oakley puffy pants too! then i can be just as good!" cough cough tanner. People aren't going to look at a 5 year old and be like "omg i wanna be like her! get me those sweet k2 skis!" Everyone (all the responses in this thread included), and companies, are going to look at her and be like wow she shreds hard. Not, "I need to look like her to be good"
Sure your sister fuckin rips, I was damn impressed at her skiing and her confidence, which is KEY. Kids that young always have tons of confidence because they don't think they're guna get hurt, or that the consequences are bad at all. Keep that confidence instilled in her, and get her in the park more, if that's what SHE wants
Give her 5-10 years and she could be super super sick.
That is, if she keeps that confidence up and keeps shredding.
Which may not be a reality, sadly