You could do it no problem, you're 3 inches shorter than me, and I'm guessing you're gonna keep growing, and I skied 177s last year, which is 6cm longer than 171s or roughly 2.5 inches, so it's very doable especially if you center mount them. It may take a few runs to get used to them, but trust me, once you get used to them you'll be glad you got the longer ski, they're so much more stable.