I think no worries. Every company seems to measure volume differently so you really don't know what it means anyway. I paddle a small Burn and I think it's about ideal for me. I'm 150 lbs so you're ~ 10% lighter, and the advertised volume of the Mamba is ~ 10% less than the Burn, so in theory the displacement per lb is about equal. But it really depends on what you're paddling, how you paddle, etc. Since you're asking this question, I'm guessing you're paddling easier water (e.g. Cl 3 & 4) and the Mamba should be fine.