Ericmerica

So i am going into my second season in skydiving and have a total of 35 jumps in the last year. I have been jumping a Spectre 190 or Sabre2 190 for the past ten jumps and have landed all of them. I have five more lands on a Sprectre 210 and I feel very comfortable landing a 190. When do you think would be an acceptable time to start jumping a 170? Oh and i weigh 175 pounds. Does any experienced jumper have an opinion? Thanks Eric